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A chemoimmunotherapy regimen combining a WT1 peptide-pulsed dendritic cell (WT1-DC) vaccine with multiagent chemotherapy modulated the tumour microenvironment (TME) toward an immunostimulatory state and enabled conversion surgery in seven of nine patients with unresectable pancreatic ductal adenocarcinoma (UR-PDAC). The authors evaluated memory CD8+ T-cell subsets among WT1-specific CTLs, antibody titres against WT1 epitopes, infiltration of CD103+ tissue-resident memory T cells and CD20+ cells in the pancreatic TME, gene mutations in plasma circulating tumour DNA (ctDNA), and PDAC cell characteristics. Before treatment, patients with relatively few WT1-specific CD8+ naive T cells, high WT1-specific IgM, no KRAS/TP53 mutations in plasma ctDNA, and low PD-L1 expression in PDAC cells had a markedly superior prognosis. WT1-targeted chemoimmunotherapy significantly increased circulating WT1-specific CD8+ central memory T cells in super-responders (PFS above median), whose central-memory to terminally differentiated effector-memory ratio was higher after 15 vaccinations; mutant ctDNA allele frequencies fell significantly after treatment. In patients with spontaneous WT1-specific cellular and humoral immunity before treatment, endogenous naive WT1-specific CD8+ T cells were converted into memory cells, yielding superior effects, and neoantigen-specific responses arose via epitope spreading (jRCTc030190195).

Myeloid-derived suppressor cells (MDSCs) play a critical role in immunotherapy. The effects of WT1 peptide-loaded dendritic cell (DC) vaccination on MDSCs were investigated in patients with acute leukaemia. WT1-DC vaccination reduced MDSCs and enhanced WT1-specific immunity; in patients in complete remission, MDSC reduction was accompanied by decreased plasma arginase 1 and indoleamine 2,3-dioxygenase and increased IL-12 and IFN-γ, whereas patients with disease progression showed increased IL-10 and TGF-β1. Reduced MDSCs correlated with WT1-specific immune activation and were associated with longer survival, indicating that WT1-DC vaccination suppresses MDSCs and improves clinical outcomes (UMIN000027279).

In this phase II trial, dendritic cell (DC) vaccination using WT1 and/or MUC1 peptides combined with chemotherapy was evaluated in 44 patients with metastatic, unresectable or recurrent non-small cell lung cancer, and immune checkpoint gene SNPs were examined as prognostic markers. DCs were given intradermally every 2–4 weeks with chemotherapy; after the seventh vaccination, four patients achieved partial response and 15 had stable disease. Median progression-free and overall survival from the start of vaccination were 6.7 and 12.3 months. Neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, prognostic nutritional index (PNI) and the PD-1 rs36084323 SNP were significantly associated with both PFS and OS, and the SNP and PNI were independent prognostic factors. DC vaccination with salvage chemotherapy appears promising in advanced or relapsed NSCLC.

Metastatic castration-resistant prostate cancer (mCRPC) has a poor prognosis. This study evaluated the safety, immune responses and outcomes of WT1 peptide-loaded dendritic cell (DC) vaccination combined with hormonal or chemotherapeutic agents; mature WT1-loaded DCs were given intradermally with OK-432 every 2–4 weeks, and WT1-specific immunity was assayed by ELISpot, HLA-tetramer and CD107a assays. Vaccination was well tolerated without severe adverse events. WT1-specific responses were significantly enhanced in patients with stable disease, with reduced regulatory T cells; a PSA reduction of more than 50% was achieved in 35.7%. Median overall survival was 28.5 months, exceeding the Halabi nomogram estimate of 19.0 months, and patients with WT1-specific immune responses had significantly longer survival.

In this phase I study, a chemoimmunotherapy regimen combining a novel WT1 peptide-pulsed dendritic cell (WT1-DC) vaccine with multiagent chemotherapy was evaluated for safety, clinical outcomes and WT1-specific immunity in unresectable advanced pancreatic ductal adenocarcinoma (UR-PDAC): stage III locally advanced (n=6), stage IV metastatic (n=3) and postoperative recurrence (n=1). Patients received one cycle of nab-paclitaxel plus gemcitabine followed by 15 doses of the WT1-DC vaccine independent of chemotherapy; the peptide cocktail comprised a multifunctional helper peptide (MHC class II, HLA-A*02:01 or A*02:06) and a killer peptide (HLA-A*24:02). The regimen was well tolerated. Among nine evaluable patients, those with long-term WT1-specific delayed-type hypersensitivity (DTH) positivity (n=4) had significantly better outcomes than short-term positive patients (n=5). Eight patients became eligible for conversion surgery, achieving R0 resection in seven and R1 in one; three of four R0-resected locally advanced cases showed long-term DTH positivity with notable T-cell and PD-1+ cell infiltration in the tumour microenvironment. All long-term DTH-positive patients were alive at least 4.5 years after starting therapy, with higher WT1-specific IFN-γ/TNF-α-producing T cells after two vaccinations and lower regulatory T cells and myeloid-derived suppressor cells after 12 vaccinations. The regimen may modulate the TME and enable conversion surgery with clinical benefit (jRCTc030190195).

This mini-review explores recent advances in cancer vaccines targeting WT1. Phase I/II trials of WT1 peptide vaccines have demonstrated safety and efficacy across cancers; early trials with HLA class I peptides evolved through combination with HLA class II peptides, improving clinical outcomes, and WT1-targeted dendritic cell vaccines have also shown favourable results. Studies in haematological malignancies report long-term remission and extended survival, and combining vaccines with immune checkpoint inhibitors has shown synergy. Current preclinical work focuses on enhancing WT1 vaccine effectiveness, underscoring the need for large-scale phase III trials.

The prognosis of relapsed or refractory acute leukaemia is poor. In this pilot study, patients with relapsed or refractory acute leukaemia were treated with WT1 peptide-loaded dendritic cells (DCs), and safety, clinical and immunological responses were examined. Eleven eligible patients were enrolled and received DCs every 2–3 weeks with OK-432 adjuvant; treatment was well tolerated. A reduction in leukaemia cells or WT1 mRNA expression was observed in four patients and maintained for a significant period, and all responding patients showed WT1-specific immune responses that may relate to outcome. Absolute numbers of regulatory T cells decreased after vaccination, suggesting reversal of immunosuppression. DC-based immunotherapy is safe and feasible in acute leukaemia.

No abstract is publicly available for this short report; the bibliographic record has been verified in PubMed (PMID 35166650). Please refer to the original article.

In this phase I/II study, WT1 and/or MUC1 peptide-loaded dendritic cell (DC) vaccination combined with gemcitabine plus nab-paclitaxel or FOLFIRINOX was evaluated in 48 patients with advanced or relapsed pancreatic ductal adenocarcinoma, who received vaccinations approximately every 2–4 weeks at least seven times. No severe vaccine-related adverse events occurred. Median progression-free and overall survival were 8.1 and 15.1 months. DC vaccination augmented tumour-specific immunity, and multivariate analysis showed that the WT1- or MUC1-specific IFN-γ ELISPOT count before vaccination was an independent prognostic factor for overall survival, indicating that DC-based immunotherapy with chemotherapy is safe and beneficial and that baseline antitumour immunity helps predict prognosis.

This phase I/II study evaluated the safety and feasibility of WT1 and/or MUC1 peptide-pulsed dendritic cell (DC) vaccination combined with chemotherapy in 65 patients with advanced or relapsed pancreatic ductal adenocarcinoma. No severe vaccine-related adverse events were observed. The objective response rate and disease control rate were 12.3% and 50.8%, and median progression-free and overall survival were 4.9 and 9.6 months. DC vaccination augmented WT1- and MUC1-specific immunity, which may relate to clinical outcome, indicating that DC-based immunotherapy combined with conventional chemotherapy is safe and feasible in advanced PDAC.

This pilot study evaluated the safety and feasibility of WT1 peptide-pulsed dendritic cell (DC) vaccination combined with OK-432 in 15 patients with advanced or relapsed oesophageal cancer. No severe vaccine-related adverse events occurred. The objective response rate and disease control rate were 20% and 40%, and median progression-free and overall survival were 4.1 and 7.0 months. WT1-pulsed DC vaccination augmented WT1-specific immunity, which may relate to outcome, indicating that DC-based immunotherapy combined with conventional chemotherapy is safe and feasible in advanced oesophageal cancer.

Pancreatic ductal adenocarcinoma has a dismal prognosis and is rarely resectable at diagnosis, so multimodal therapy is needed to improve long-term survival. Six eligible patients received multimodal therapy comprising dendritic cells pulsed with HLA class I (A*24:02 or A*02:06)-restricted WT1 peptide (DC/WT1-I), chemotherapy, radiation and/or surgery; laboratory data, DC/WT1-I-specific delayed-type hypersensitivity and WT1-specific immune responses were analysed as prognostic markers. Multimodal therapy involving three to four treatment types was significantly associated with longer overall survival than two-type combinations (p=0.0177), and after seven vaccinations, patients with a neutrophil-to-lymphocyte ratio or CRP below the median had superior progression-free survival (p=0.0246). Patients surviving more than 1000 days maintained WT1-specific immune responses over the long term.

The association between the immunological status of the pancreatic ductal adenocarcinoma (PDA) microenvironment and prognosis was assessed. A high tumour-infiltrating lymphocyte (TIL) density was associated with better prognosis, but even with high TIL density, PD-L1-expressing PDA cells conferred worse prognosis than PD-L1-negative tumours. A significant association was observed between better prognosis and a microenvironment with high TIL density and negative PD-L1 expression, suggesting that combined immunological assessment may predict prognosis after surgical resection.

The safety and feasibility of vaccination with WT1 peptide-loaded dendritic cells (DCs) plus OK-432 adjuvant combined with conventional chemotherapy were investigated in 11 patients with metastatic or relapsed head and neck squamous cell carcinoma. No severe vaccine-related adverse events occurred; five patients had durable stable disease and six progressed after vaccination. Median progression-free and overall survival were 6.4 and 12.1 months. DC vaccination augmented WT1-specific immunity, which may relate to outcome, indicating that DC-based immunotherapy with chemotherapy is safe and feasible in advanced HNSCC.

This pilot study examined the immune response to WT1 peptide-pulsed DC vaccination combined with docetaxel (DCDOC) in advanced esophageal cancer after first-line chemotherapy. Ten HLA-A*2402 patients received docetaxel 50 mg/m² on day 1 and DC vaccination (1×10^7 cells) on days 15 and 22, every 4 weeks for 3 cycles; WT1-specific immunity was evaluated by DTH, HLA tetramer and IFN-γ ELISPOT. Median overall survival was 5 months; no clinical effect was observed, only one patient completed the protocol, nine progressed and one died during cycle 2, so safety could not be evaluated. However, WT1-specific responses were demonstrated in six patients and correlated with a low percentage of CD11b+/CD66b+ granulocytic myeloid-derived suppressor cells among CD15+ cells. DCDOC elicited WT1-specific immunity despite docetaxel-related myelosuppression, supporting future evaluation as adjuvant therapy (UMIN000006704).

Eight patients with resectable pancreatic cancer undergoing surgery combined with S-1 or S-1 plus gemcitabine were enrolled to examine the safety of a WT1 peptide-pulsed dendritic cell (WT1-DC) vaccine combined with chemotherapy; WT1 immunohistochemistry was performed in 34 pancreatic cancers. No serious side effects occurred apart from grade 1 fever in five patients and grade 1 injection-site reactions in all. WT1-specific cytotoxic T lymphocytes were detected in seven patients, and WT1 and HLA class I were positive in all 34 cases. The study clarified safety and the potential acquisition of WT1-targeted immunity; efficacy for prognosis awaits a prospective trial in resectable pancreatic cancer.

WT1 peptide vaccination has shown potential in several cancers, and the adjuvant OK-432 has potent immunomodulatory properties that may help trigger appropriate immune responses in paediatric solid tumour patients. Paediatric patients received WT1 peptide with OK-432 every 2 weeks for seven doses; 18 of 24 completed the schedule. Sixteen had local skin symptoms and/or fever, and one had anaphylactic symptoms at the final injection that quickly subsided with treatment. WT1-specific immune responses were seen in four patients (22.2%), and WT1 and HLA class I were expressed in 100% and 85% of primary tumours. The regimen appears relatively safe in children, though larger studies are needed to confirm safety and efficacy.

Surgical resection is the only curative treatment for pancreatic ductal adenocarcinoma (PDA), yet some patients succumb shortly after complete resection. Because WT1 plays an oncogenic role in various tumours, WT1 protein expression was analysed in 50 consecutive PDA patients resected at The Jikei University Kashiwa Hospital (2005–2015) by immunohistochemistry and assessed against overall and disease-free survival, together with laboratory and systemic inflammatory markers within 2 weeks of surgery. WT1 was detected in the nucleus and cytoplasm of all PDA cells and in tumour vessels; nuclear staining was weak in all cases whereas cytoplasmic intensity varied, and its pattern was analysed in relation to prognosis.

The safety and feasibility of WT1 peptide-loaded dendritic cell (DC) vaccination with OK-432 adjuvant combined with molecular targeted therapy or conventional chemotherapy were investigated in five patients with metastatic or relapsed renal cell carcinoma (RCC) and five with bladder cancer (BC). No severe vaccine-related adverse events occurred; seven patients with RCC or non-muscle-invasive BC had durable stable disease and three progressed. DC vaccination augmented WT1-specific immunity and reduced regulatory T cells, which may relate to outcome, indicating that the combination is safe and feasible in advanced RCC or BC.

A 77-year-old man with invasive bladder cancer (urothelial carcinoma, G2–3, pT4) causing bilateral hydronephrosis underwent total cystectomy with bilateral cutaneous ureterostomy, followed by two courses of adjuvant gemcitabine plus cisplatin. One year after surgery, pelvic lymph node metastasis, peritoneal dissemination with ascites and a subcutaneous metastasis appeared rapidly, and immunotherapy was started in May 2014: lymphokine-activated killer cell therapy plus dendritic cell vaccine therapy for 4 months, then dendritic cell vaccine therapy alone. Four months after starting immunotherapy, the metastatic lesions had disappeared on imaging and all previously elevated tumour markers (CEA, CA125, TPA, HER2) had normalized. No particular side effects occurred, and no recurrence has been observed for 3 years since the start of treatment.

The feasibility and efficacy of a peptide-pulsed dendritic cell vaccine combined with carboplatin and paclitaxel (DCCP) were evaluated in stage IV melanoma patients previously treated with dacarbazine-containing regimens. Six HLA-A24 and three HLA-A02 patients received carboplatin (AUC 5) and paclitaxel (175 mg/m²) on day 1 and DCs (2×10^7) pulsed with WT1, gp100, tyrosinase and MAGE-A3 (A24) or MAGE-A2 (A02) peptides on days 8 and 22 of 28-day cycles for up to three cycles. DCCP was well tolerated; median progression-free and overall survival were 2.3 and 12.0 months. A WT1-specific immune response was detected in four of nine patients and was more likely with the HLA-A24-restricted peptide (75% vs 0%, P=0.058). Three of four responders (75%) survived beyond 12 months versus one of five (20%) non-responders who received a BRAF inhibitor after DCCP.

Pancreatic ductal adenocarcinoma (PDA) has a very poor prognosis despite novel chemotherapy, and most patients relapse within 5 years even after complete resection, so new targeted vaccines are urgently needed. The WT1 antigen was ranked as an excellent antigen among 75 tumour-associated antigens in a National Cancer Institute prioritization project based on factors such as therapeutic function. WT1-targeted vaccines act not only on PDA cells but also on angiogenesis and immunosuppressive cells such as myeloid-derived suppressor cells in the PDA microenvironment, and WT1 is increased in PDA cells, making it an effective therapeutic target. A novel WT1 peptide with increased immunogenicity has been developed and used in clinical trials; this review summarizes the clinical results.

Colorectal cancer (CRC) is among the most common cancers and a leading cause of cancer-related death. Although systemic therapy is standard for recurrent or metastatic CRC, prognosis remains extremely poor and the optimal sequence of therapy is unknown, so alternative strategies such as immunotherapy are needed. This review summarizes evidence from dendritic cell-based immunotherapy strategies currently in clinical trials and discusses the potential for antitumour immune responses through blockade of the immunoinhibitory PD-1/PD-L1 pathway in patients with CRC.

Elevated neutrophil-to-lymphocyte ratio (NLR) has been linked to poorer prognosis in pancreatic cancer, but its relation to immunohistochemical (IHC) findings was unclear. Clinicopathological data from 28 consecutive patients who underwent resection at The Jikei University Kashiwa Hospital (2008–2012) were analysed. Kaplan–Meier analysis showed NLR ≥5 to be a factor for decreased disease-free and overall survival (p=0.003, p<0.001). The density of CD163+ macrophages and CD66b+ neutrophils was significantly higher in the high-NLR group, whereas CD20+ lymphocytes were denser in the low-NLR group, and NLR correlated significantly with CD20+ and CD163+ cell densities.

Despite novel chemotherapy, pancreatic ductal adenocarcinoma (PDA) remains lethal, and new targeted cancer vaccines may be a viable option. WT1 is among the most widely expressed tumour-associated antigens, including in PDA, and WT1-targeted vaccines have shown potent antitumour effects when combined with chemotherapy in preclinical and clinical studies. This review summarizes early-phase clinical trials of WT1-targeted vaccines (peptide and dendritic cell-based) for PDA and discusses future strategies combining WT1-specific vaccines with immune checkpoint therapies to maximize clinical effectiveness.

The incidence of pancreatic ductal adenocarcinoma (PDA) is rising and prognosis is extremely poor; gemcitabine- or 5-FU-based chemotherapy is standard, but most patients do not survive beyond 1 year, so alternative approaches are imperative. As PDA cells express numerous tumour-associated antigens suitable as vaccine targets, cancer vaccines are promising. Cell-based cancer vaccines, generated mainly by presenting whole tumour cells or dendritic cells to immune cells, have shown encouraging preclinical results and have been explored in several clinical trials for PDA; chemotherapy and cancer vaccines can also synergize. This review discusses these advances.

"Vaccell" is a dendritic cell (DC)-based cancer vaccine established in Japan. DCs play central roles in antigen presentation and in deciding the direction of host immune reactions. The authors showed that DCs treated with the streptococcal adjuvant OK-432 produce IL-12, induce a Th1-dominant state and elicit antitumour effects more powerful than DCs treated with known maturation factors, and therefore matured DCs with OK-432 to make Vaccell. A retrospective analysis of 255 patients with inoperable pancreatic cancer who received standard chemotherapy plus DC vaccines showed significantly prolonged survival in patients with a positive delayed-type hypersensitivity skin reaction, suggesting that responders exist. A small prospective study was then conducted using DCs pulsed with WT1 peptides including an HLA class II-restricted peptide.

This phase I pilot study evaluated the feasibility of, and immune response to, WT1 peptide-pulsed DC vaccination combined with gemcitabine (DCGEM) as first-line therapy for advanced pancreatic cancer. Ten HLA-A*2402 patients received DC vaccination (1×10^7 cells) on days 8 and 22 and gemcitabine (1000 mg/m²) on days 1, 8 and 15. WT1-specific immunity was assessed by DTH skin test, IFN-γ ELISPOT and HLA tetramer assays. DCGEM was well tolerated with a gemcitabine relative dose intensity of 87%. Disease control was seen in all three DTH-positive patients and was associated with a low neutrophil/lymphocyte ratio and a low percentage of granulocytic myeloid-derived suppressor cells before treatment. Patients with liver metastases and high inflammatory markers (CRP, IL-8) had poor survival despite WT1-specific responses. The regimen was feasible and induced anti-tumour T-cell responses, supporting further study in patients without liver metastases and with favourable immunological conditions (UMIN000004855).

A phase I study of the safety and immunomonitoring of WT1-pulsed DC vaccination in relapsed malignant glioma. Approximately 1–2×10^7 DCs loaded with WT1 peptide and/or autologous tumour lysate were injected intradermally into the axillae with OK-432 every 2 weeks for at least 5–7 sessions during individual chemotherapy. Ten patients (3 men, 7 women; median age 39) with glioblastoma (6), anaplastic astrocytoma (2), anaplastic oligoastrocytoma (1) and anaplastic oligodendroglioma (1) were enrolled; 7 received modified WT1-pulsed DCs, 2 lysate-pulsed DCs and 1 both. Five patients on WT1-pulsed DCs had stable disease, two of whom showed neurological improvement and tumour shrinkage on MRI. No serious adverse events occurred apart from grade 1–2 injection-site erythema. WT1-reactive cytotoxic T cells were detected after vaccination, and injection-site skin reactions were positive in 8 of 10 patients and persisted to the final session. The study demonstrated safety, immunogenicity and feasibility in relapsed malignant glioma.

To elucidate the immunologic mechanisms of artificially synthesized helper/killer-hybrid epitope long peptide (H/K-HELP), which had shown vaccine efficacy in human cancers, OVA-H/K-HELP was prepared by conjugating killer and helper epitopes of the model antigen ovalbumin via a glycine linker. Vaccination of C57BL/6 mice with the 30-amino-acid OVA-H/K-HELP plus CpG-ODN adjuvant, but not with a mixture of the short class I (8-mer) and class II (17-mer) peptides, induced higher numbers of OVA-tetramer-positive CTLs together with IFN-γ-producing CD4+ Th1 cells; replacing or shortening the glycine linker reduced efficacy. H/K-HELP was selectively taken up and presented by dendritic cells in draining lymph nodes, sustained stimulation of both CTL and Th1 cells over time, and induced rejection of established tumours that short peptides could not.

Treatment combining dendritic cells pulsed with three MHC class I/II-restricted WT1 peptides (DC/WT1-I/II) with chemotherapy may stabilise disease in pancreatic cancer. Laboratory data from seven patients receiving combined DC/WT1-I/II vaccination and chemotherapy were analysed, with DC phenotypes and plasma cytokines assessed by flow cytometry. The post-treatment neutrophil-to-lymphocyte ratio was a treatment-related prognostic factor for better survival, and mean fluorescence intensities of HLA-DR and CD83 on DCs increased significantly after chemoimmunotherapy, whereas plasma IL-6 rose significantly in non-super-responders. These markers may predict longer survival in advanced pancreatic cancer patients undergoing chemoimmunotherapy.

The association of plasma IL-6 and IL-8 with WT1-specific immune responses and outcomes was investigated in pancreatic ductal adenocarcinoma patients treated with dendritic cells pulsed with three MHC class I/II-restricted WT1 peptides plus chemotherapy. Plasma IL-6/IL-8 were measured by ELISA throughout treatment, and WT1-specific immunity by delayed-type hypersensitivity (DTH). Three of seven patients showed strong WT1-DTH throughout long-term vaccination with significantly decreased IL-6/IL-8 after vaccination; overall survival was significantly longer in patients with low plasma IL-6 (<2 pg/mL) after five vaccinations (P=0.025). After progression, WT1-DTH declined and became negative at the terminal stage. Sustained low IL-6/IL-8 was associated with WT1-specific DTH and long-term survival.

A 15-year-old girl with acute lymphoblastic leukaemia received allogeneic dendritic cell vaccination pulsed with WT1 peptide after her third haematopoietic stem cell transplantation; the vaccines were generated from the third transplant donor, her 12-year-old sister. She received 14 vaccines with no graft-versus-host disease or systemic adverse effects apart from a grade 2 injection-site skin reaction. WT1-specific immune responses were detected after vaccination by both WT1-tetramer analysis and ELISPOT. The strategy may be safe, tolerable and feasible for patients relapsing after transplantation.

A phase I trial of DCs pulsed with a mixture of three WT1 peptides (MHC class I- and II-restricted epitopes) combined with chemotherapy, assessing safety, clinical response and WT1-specific immunity. Ten patients with stage IV pancreatic ductal adenocarcinoma and one with intrahepatic cholangiocarcinoma received one course of gemcitabine followed by biweekly intradermal mature DCs pulsed with class I (n=3), class II (n=1) or class I/II (n=7) WT1 peptides plus gemcitabine. Treatment was well tolerated. WT1-specific IFN-γ-producing CD4+ T cells increased significantly with class I/II DCs, and WT1-specific DTH was detected in 4 of 7 such patients versus 0 of 3 with single-class DCs. DTH-positive patients had significantly better overall and progression-free survival; the three with strong DTH reactions had a median OS of 717 days. Activation of WT1-specific immunity by class I/II DCs with chemotherapy may be associated with disease stability in advanced pancreatic cancer.

The authors designed a phase 1 study using dendritic cells pulsed with a mixture of three WT1 peptides including MHC class I/II-restricted epitopes (DC/WT1-I/II). Their recent work reveals that the combination of DC/WT1-I/II and chemotherapy induced long-term WT1-specific CD4+ and CD8+ T-cell responses.

Whether serum IL-8 reflects the tumour microenvironment and has prognostic value in oral squamous cell carcinoma (OSCC) was investigated in 50 patients who underwent radical resection. Preoperative serum IL-8 was measured by ELISA, and tumour IL-8 expression and immune-cell infiltration were analysed immunohistochemically. Disease-free survival was significantly longer in stage I/II patients with low serum IL-8 (p=0.001). Tumour IL-8 expression and CD163+ cell density at the invasive front correlated with serum IL-8 and were associated with poor outcome, and multivariate analysis showed N status, tumour IL-8 and CD163+ infiltration significantly affected disease-free survival, suggesting a new criterion for relapse risk.

Cryotherapy induces antitumour immunity in mice, but the effects of freezing-induced immunomodulation in breast cancer patients were unclear. Ten patients were prospectively divided into cryotherapy followed by surgical excision or excision alone, and cytokine profiles of plasma and PBMCs were analysed by flow cytometry after in vitro stimulation with a 30-mer MUC1 peptide. No differences in IFN-γ-producing CD4+ or CD8+ T cells or in plasma cytokines (IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, TNF-α, TNF-β) were observed between the groups, and no alteration of type 1/2 helper cytokine profiles was detected with cryotherapy alone.

Novel helper epitope peptides of the Survivin cancer antigen presented by both HLA-DRB1*01:01 and DQB1*06:01 were identified; the helper epitope also contained three Survivin killer epitopes presented by HLA-A*02:01 and A*24:02. This 19-amino-acid peptide (SU18) induced only weak Survivin-specific CD4+ and CD8+ T-cell responses despite containing both epitope types. To enhance efficacy, SU18 was conjugated via a glycine linker to another DR53-restricted helper epitope (SU22), creating a 40-amino-acid Survivin-H/K-HELP containing two helper and three killer epitopes. Survivin-H/K-HELP activated IFN-γ-producing CD4+ Th1 and CD8+ Tc1 cells more strongly than the mixture of its component peptides in the presence of OK-432-treated monocyte-derived DCs, and H/K-HELP-pulsed DCs showed sustained antigen presentation to Survivin-specific Th1 cells.

Eighty-one patients with oral squamous cell carcinoma received oral fluoropyrimidine UFT and radiotherapy (RT) with or without the immunotherapeutic agent OK-432. Overall and progression-free survival were significantly longer with RT+UFT+OK-432 than with RT+UFT (P=0.0075 and P=0.0175), and clinical response was more favourable (P=0.0066). In vitro, OK-432-stimulated PBMCs produced Th1 cytokines as well as IL-10 and TGF-β (from Th2 and regulatory T cells, which inhibit antitumour immunity); 5-FU and/or X-ray significantly inhibited OK-432-induced IL-10 and TGF-β but not Th1 cytokines, and suppressed GATA-3 and Foxp3 mRNA (Th2/Treg transcription factors) but not T-bet (Th1).

Antitumour functions of host immunity are often compromised in cancer patients. The relationship between the Bcl-2/Bax mRNA expression ratio in peripheral blood mononuclear cells and clinical outcome was evaluated in head and neck carcinoma. Overall survival tended to be longer with Bcl-2/Bax ≥1.2 (P=0.084, n=61) and disease-free survival was significantly longer (P=0.001, n=76); all patients with a ratio ≥2.0 were alive at 36 months and disease-free at 24 months. In 56 patients receiving immunochemoradiotherapy with UFT and OK-432 plus radiotherapy, the ratio was significantly related to RECIST response and IFN-γ production.

The incidence of colorectal cancer (CRC) is rising and prognosis for recurrent or metastatic disease is extremely poor; integrating alternative strategies such as immunotherapy is imperative. This review discusses immunotherapy for inducing cytotoxic T lymphocytes and the major approaches for CRC in clinical trials, including peptide vaccines, dendritic cell-based vaccines, whole tumour cell vaccines, viral vector-based vaccines, adoptive cell transfer, antibody-based immunotherapy and cytokine therapy, together with the possibility of combination therapies and the challenges of tumour escape mechanisms.

The rationale for fusing dendritic cells (DCs) with whole tumour cells is that DCs are potent antigen-presenting cells whereas tumour cells express a constellation of tumour-associated antigens. Although administration of DC/tumour cell fusions is safe and triggers efficient tumour-specific T-cell responses in vitro, few objective clinical responses have been reported. This review discusses novel approaches to improve the immunogenicity of DC/malignant cell fusions as anticancer vaccines.

Various strategies deliver tumour-associated antigens (TAAs) to dendritic cells (DCs). Fusion of DCs and whole cancer cells can process a broad array of TAAs, including unidentified molecules, and present them with MHC class I and II molecules and co-stimulatory signals. DC–cancer cell fusions stimulate potent antitumour immunity in animal models, but antitumour effects in early clinical trials have been less vigorous than in preclinical settings. This mini-review summarizes recent advances in such fusion-based vaccines.

Forty-nine patients with inoperable pancreatic carcinoma refractory to standard treatment received DC-based immunotherapy (DC vaccine alone or DC vaccine plus lymphokine-activated killer [LAK] cell therapy) combined with gemcitabine and/or S-1. Two patients achieved complete remission, five partial remission and ten stable disease; median survival was 360 days, suggesting prolonged survival. Survival was longer in patients who also received LAK cell therapy. Increased cancer antigen-specific cytotoxic T cells and decreased regulatory T cells were observed in several patients, with longer survival tending to associate with the latter. No grade 3 or worse adverse events occurred. DC vaccine-based immunotherapy combined with chemotherapy was safe and possibly effective in this refractory population.

A patient with pulmonary metastasis of colon cancer was treated with an artificially synthesised helper/killer-hybrid epitope long peptide (H/K-HELP) of the MAGE-A4 cancer antigen, vaccinated with MAGE-A4-H/K-HELP combined with OK-432 and Montanide ISA-51. No severe side effects occurred apart from an injection-site skin reaction. MAGE-A4-H/K-HELP induced MAGE-A4-specific Th1 and Tc1 immune responses and MAGE-A4-specific complement-fixing IgG antibodies, and tumour growth and the CEA tumour marker were significantly decreased at the final diagnosis. This is the first report that a synthesised MAGE-A4-H/K-HELP induces Th1-dependent cellular and humoral immunity in a human cancer patient.

Neurokinin A (NKA) controls responses such as airway contraction through neurokinin-2 receptor (NK2R) signalling, but its role in immunity was poorly defined. NK2R-mediated neuropeptide signalling was shown to activate dendritic cell (DC)-mediated type 1 immune responses: IFN-γ markedly induced NK2R mRNA and surface protein in bone marrow-derived DCs and increased DC-derived NKA in vivo and in vitro; NKA induced type 1 IFN mRNA in DCs; NK2R transduction augmented surface MHC class II and antigen-specific IL-2 production by CD4+ T cells; and an NK2R antagonist significantly suppressed IFN-γ production by CD4+ and CD8+ T cells stimulated with antigen-loaded DCs. IFN-γ or TLR3 ligand also induced NK2R in human PBMC-derived DCs.

For decades cancer vaccine therapy focused only on CTL activation, achieving long stable disease but limited therapeutic effect; failure derives from strong tumour escape mechanisms and neglect of helper T-cell activation. The authors have proposed that Th1-dominant immunity is critical for overcoming immunosuppressive escape mechanisms to induce tumour-specific CTLs, which are essential for complete cure and prevention of recurrence. Applying these findings, they started clinical trials of a novel cancer vaccine/cell therapy using H/K-HELP of MAGE-A4 or Survivin: in phase I, H/K-HELP containing killer and helper epitopes plus Th1 adjuvants (OK-432 and Montanide) was given subcutaneously four times at 2-week intervals, and both MAGE-A4- and Survivin-H/K-HELP induced cancer-specific Th1 and Tc1 responses and complement-fixing IgG1/IgG3 antibodies.

Feasibility and efficacy of DC therapy were assessed in advanced papillary and follicular thyroid cancer with refractory distant metastases. Six Japanese patients (2 men, 4 women; aged 46–72; papillary 5, follicular 1) received 10^7 autologous tumour lysate-pulsed monocyte-derived mature DCs weekly for 4 weeks then fortnightly for 8 weeks (8 vaccinations), with low-dose IL-2 (350 KIU) for 3 days at each vaccination. Clinical response, adverse effects, DTH and IFN-γ production by peripheral CD3+ lymphocytes were evaluated. Disease was stable in 2 and progressive in 4 patients; no adverse events were observed, and DTH and IFN-γ results did not correlate with clinical response. DC immunotherapy could be administered without substantial side effects.

The relationship between Bcl-2 and Bax gene expression and therapeutic effect was investigated in oral cancer patients. The Bcl-2/Bax expression ratio in peripheral blood mononuclear cells correlated significantly with the therapeutic effect of radiotherapy combined with UFT and OK-432 and with survival rate, and also with OK-432-induced IFN-γ and NK activity. Bcl-2 and Bax expression in PBMCs may be useful as a prognostic factor in oral cancer.

Cancer-testis (CT) antigens are attractive immunotherapy targets because they are expressed in many malignancies but only in testis among normal adult tissues. To evaluate MAGE-A4 and NY-ESO-1 as vaccine targets in non-small cell lung carcinoma (NSCLC), their expression and T-cell infiltration were examined in 157 patients by RT-PCR and immunohistochemistry, with survival analysis. MAGE-A4 and NY-ESO-1 were expressed in 40 of 141 (28.4%) and 13 of 157 (8.3%) tumours, more frequently in squamous cell carcinoma than adenocarcinoma. MAGE-A4 expression inversely correlated with survival in advanced stages, and combined infiltration of CD4+ and CD8+ T cells into tumour nests predicted better survival, with no correlation between lymphocyte infiltration and antigen expression.

WT1 is overexpressed in leukaemias and many solid tumours and is an attractive target antigen for immunotherapy. This phase I study reports WT1 peptide-based immunotherapy in patients with breast or lung cancer, myelodysplastic syndrome (MDS) or acute myeloid leukaemia. An HLA-A*2402-restricted natural or modified 9-mer WT1 peptide emulsified in Montanide ISA51 was injected intradermally at 0.3, 1.0 or 3.0 mg every 2 weeks, with toxicity and clinical and immunological responses as principal endpoints. Twenty-six patients received at least one vaccination and 18 completed three or more. Toxicity was limited to local erythema in patients with adequate normal haematopoiesis, whereas severe leukocytopenia occurred in MDS patients whose abnormal haematopoiesis derived from WT1-expressing transformed stem cells. Twelve of 20 evaluable patients showed clinical responses such as reduction in leukaemic blasts, tumour size or tumour markers, and increases in WT1-specific CTL frequency correlated clearly with clinical response, demonstrating that WT1 vaccination can induce WT1-specific CTLs and cancer regression without damage to normal tissues.

OK-432 (Picibanil), a streptococcal preparation with potent biological response-modifying activity, was approved in Japan as an anticancer agent in 1975, and extensive clinical and experimental data have since accumulated showing that it induces cytokines, activates immune cells and augments anticancer immunity. Recent work on innate and adaptive immunity showed that OK-432 acts at least partly via the Toll-like receptor 4-MD2 pathway, and dendritic cells (DCs), central to immune responses, are matured by OK-432 in vitro and in vivo. These findings suggest OK-432 is a useful adjuvant for DC-based immunotherapy, and clinical studies of DC therapy with OK-432 are under way.

The discovery of many tumour antigens demonstrated that host lymphocytes can recognise and destroy tumour cells, as proposed in the cancer immunosurveillance hypothesis, and the cancer immunoediting concept indicates that host immunity both protects against cancer and selects tumours that escape immune attack. Although T cells can destroy spontaneously arising tumours, antitumour immunity is often hard to generate in tumour-bearing hosts because of negative regulatory mechanisms. This review summarises the authors' work using activation of type-1 innate and/or acquired immunity as a strategy to overcome immunosuppression, including tumour-vaccine therapy and other protocols aimed at activating type-1 immunity.

A pilot study of vaccination with mature DCs (mDCs) plus low-dose IL-2 in stage IV melanoma resistant to conventional therapy. Autologous monocytes from a single apheresis were cultured 7 days with GM-CSF and IL-4 to yield immature DCs, cryopreserved, then exposed to autologous tumour lysate and TNF-α for 4 days before vaccination. Patients received 10^7 mDCs weekly for 10 weeks with IL-2 350–700 kIU three times weekly. Of 10 patients, one had stable disease, seven progressive disease and two mixed responses including partial regression, who received 20 further injections. Adverse events were minimal (local skin reactions, mild fever; NIH-CTC grade 0–1). Median survival from first vaccination was 240 days (31–735). Patient-derived DCs showed reduced CD1a, CD86 and HLA-DR expression and attenuated antigen uptake, chemotaxis and presentation in vitro. Although clinical efficacy requires further research, autologous lysate-pulsed mDCs could be safely harvested, cryopreserved and administered.

Augmenting the anticancer host response is important in cancer treatment, and signalling via Toll-like receptors (TLRs), newly identified receptors recognising many pathogens, is implicated in inducing anticancer immunity. Seya et al. showed that DC maturation and cytokine induction by BCG cell wall skeleton involve TLR2 and TLR4, and Akira et al. discovered TLR9, which recognises unmethylated bacterial CpG-DNA and is expected to be a potent inducer of Th1 responses; TLR9-deficient mice show no response to CpG-DNA. The authors obtained two molecules—a lipoteichoic acid-related molecule from OK-432 and a plant-derived 55-kDa protein—that induce Th1 responses and strong anticancer effects in vivo and in vitro, and their experiments indicate these act through TLR signalling.