Takeshi Ishii

Phase I vaccination trial of SYT-SSX junction peptide in patients with disseminated synovial sarcoma

BackgroundSynovial sarcoma is a high-grade malignant tumor of soft tissue, characterized by the specific chromosomal translocation t(X;18), and its resultant SYT-SSX fusion gene. Despite intensive multimodality therapy, the majority of metastatic or relapsed diseases still remain incurable, thus suggesting a need for new therapeutic options. We previously demonstrated the antigenicity of SYT-SSX gene-derived peptides by in vitro analyses. The present study was designed to evaluate in vivo immunological property of a SYT-SSX junction peptide in selected patients with synovial sarcoma.MethodsA 9-mer peptide (SYT-SSX B: GYDQIMPKK) spanning the SYT-SSX fusion region was synthesized. Eligible patients were those (i) who have histologically and genetically confirmed, unresectable synovial sarcoma (SYT-SSX1 or SYT-SSX2 positive), (ii) HLA-A*2402 positive, (iii) between 20 and 70 years old, (iv) ECOG performance status between 0 and 3, and (v) who gave informed consent. Vaccinations with SYT-SSX B peptide (0.1 mg or 1.0 mg) were given subcutaneously six times at 14-day intervals. These patients were evaluated for DTH skin test, adverse events, tumor size, tetramer staining, and peptide-specific CTL induction.ResultsA total of 16 vaccinations were carried out in six patients. The results were (i) no serious adverse effects or DTH reactions, (ii) suppression of tumor progression in one patient, (iii) increases in the frequency of peptide-specific CTLs in three patients and a decrease in one patient, and (iv) successful induction of peptide-specific CTLs from four patients.ConclusionsOur findings indicate the safety of the SYT-SSX junction peptide in the use of vaccination and also give support to the property of the peptide to evoke in vivo immunological responses. Modification of both the peptide itself and the related protocol is required to further improve the therapeutic efficacy.

Extraskeletal myxoid chondrosarcoma : a multi-institutional study of 42 cases in Japan

Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant neoplasm. Despite a consensus for the distinct clinicopathologic entity of EMC, its clinical features remain controversial. In addition, most studies have contained a small number of patients who underwent definitive surgical treatment.

Detection and Induction of CTLs Specific for SYT-SSX-Derived Peptides in HLA-A24+ Patients with Synovial Sarcoma

To investigate the immunogenic property of peptides derived from the synovial sarcoma-specific SYT-SSX fusion gene, we synthesized four peptides according to the binding motif for HLA-A24. The peptides, SS391 (PYGYDQIMPK) and SS393 (GYDQIMPKK), were derived from the breakpoint of SYT-SSX, and SS449a (AWTHRLRER) and SS449b (AWTHRLRERK) were from the SSX region. These peptides were tested for their reactivity with CTL precursors (CTLps) in 16 synovial sarcoma patients using HLA-A24/SYT-SSX peptide tetramers and also for induction of specific CTLs from four HLA-A24+ synovial sarcoma patients. Tetramer analysis indicated that the increased CTLp frequency to the SYT-SSX was associated with pulmonary metastasis in synovial sarcoma patients (p < 0.03). CTLs were induced from PBLs of two synovial sarcoma patients using the peptide mixture of SS391 and SS393, which lysed HLA-A24+ synovial sarcoma cells expressing SYT-SSX as well as the peptide-pulsed target cells in an HLA class I-restricted manner. These findings suggest that aberrantly expressed SYT-SSX gene products have primed SYT-SSX-specific CTLps in vivo and increased their frequency in synovial sarcoma patients. The identification of SYT-SSX peptides may offer an opportunity to design peptide-based immunotherapeutic approaches for HLA-A24+ patients with synovial sarcoma.

Clinical outcome of patients with Ewing sarcoma family of tumors of bone in Japan: The Japanese musculoskeletal oncology group cooperative study

Ewing sarcoma family of tumors (ESFT) of bone is extremely rare in Japan. The objectives of the current study were to assess the clinical outcome and prognostic factors of patients with ESFT of bone in Japan and to compare them between Euro‐American and Japanese populations.

Prognostic impact and immunogenicity of a novel osteosarcoma antigen, papillomavirus binding factor, in patients with osteosarcoma

To develop peptide‐based immunotherapy for osteosarcoma, we previously identified papillomavirus binding factor (PBF) as a cytotoxic T lymphocytes (CTL)‐defined osteosarcoma antigen in the context of human leukocyte antigen (HLA)‐B55. In the present study, we analyzed the distribution profile of PBF in 83 biopsy specimens of osteosarcomas and also the prognostic impact of PBF expression in 78 patients with osteosarcoma who had completed the standard treatment protocols. Next, we determined the antigenic peptides from PBF that react with peripheral T lymphocytes of HLA‐A24+ patients with osteosarcoma. Immunohistochemical analysis revealed that 92% of biopsy specimens of osteosarcoma expressed PBF. PBF‐positive osteosarcoma conferred significantly poorer prognosis than those with negative expression of PBF (P = 0.025). In accordance with the Bioinformatics and Molecular Analysis Section score, we synthesized 10 peptides from the PBF sequence. Subsequent screening with an HLA class I stabilization assay revealed that peptide PBF A24.2 had the highest affinity to HLA‐A24. CD8+ T cells reacting with a PBF A24.2 peptide were detected in eight of nine HLA‐A24‐positive patients with osteosarcoma at the frequency from 5 × 10−7 to 7 × 10−6 using limiting dilution/mixed lymphocyte peptide culture followed by tetramer‐based frequency analysis. PBF A24.2 peptide induced CTL lines from an HLA‐A24‐positive patient, which specifically killed an osteosarcoma cell line that expresses both PBF and HLA‐A24. These findings suggested prognostic significance and immunodominancy of PBF in patients with osteosarcoma. PBF is the candidate target for immunotherapy in patients with osteosarcoma. (Cancer Sci 2008; 99: 368–375)

Crisscross CTL Induction by SYT-SSX Junction Peptide and Its HLA-A*2402 Anchor Substitute

To investigate the effects of anchor substitutions in SYT-SSX junction peptide, an HLA-A24 anchor residue (position 9) of the SYT-SSX B peptide (GYDQIMPKK) was substituted to more favorable residues according to the HLA-A24-binding motif. Among four substitutes constructed, a substitute with isoleucine (termed K9I peptide) most apparently enhanced the affinity for HLA-A24 molecule. Subsequent in vitro CTL induction analysis using PBMCs of 15 HLA-A24+ synovial sarcoma patients revealed that the original B peptide allowed to induce synovial sarcoma-specific CTLs from 7 patients (47%), whereas such CTLs were inducible from 12 patients (80%) with K9I peptide. Moreover, the extent of cytotoxicity against HLA-A24+ synovial sarcoma cell lines was higher in K9I peptide-induced CTLs than B peptide-induced CTLs. Influence of anchor substitution on peptide/TCR interaction was evaluated by cytotoxicity assays against autologous cells and tetramer analysis. CTLs induced from a synovial sarcoma patient using K9I peptide did not lyse autologous PHA blasts or EBV-infected B cells. In vitro stimulations of PBMCs from 5 HLA-A24+ synovial sarcoma patients with K9I peptide increased the frequency of T cells reacting with both HLA-A24/K9I peptide tetramer and HLA-A24/B peptide tetramer. In contrast, the frequency of T cells reacting with HLA/HIV-derived peptide tetramer remained low. These findings support the validity in design of anchor residue substitution in SYT-SSX fusion gene-derived peptide, and provide a potential clue to the current stagnation in vaccination trials of fusion gene-derived natural junction peptides.

Outcome of Treatment for Osteosarcoma of the Extremities Over the Last 20 Years: Report from 11 Referral Centers in Japan

The survival of patients with osteosarcoma has improved dramatically due to the introduction of effective systemic chemotherapy. The key standard drugs for osteosarcoma chemotherapy are methotrexate, doxorubicin, and cisplatin, and multi-institutional trials based on these drugs have been conducted in Japan since the 1990s. However, there have been no nationwide data on treatment outcome, especially with regard to survival and prognostic factors. In this chapter, therefore, we present data from a large nationwide cohort of patients with osteosarcoma treated at 11 referral centers in Japan during the period 1990–2010 with special reference to survival and relevant prognostic factors. The 3-, 5-, and 10-year metastasis-free survival and overall survival rates for the 529 patients were 70 %, 64 %, and 62 % and 88 %, 83 %, and 77 %, respectively. The prognosis for patients with osteosarcoma in Japan was comparable to, or slightly better than, those reported in other countries. International collaboration should also be conducted in Asian countries including Japan to improve the outcome further and find the optimal treatment for osteosarcoma.

The Evaluation of Clinical Prognostic Factors in Osteosarcomas

During the past 15 years, dramatic changes have been made in the treatment of osteosarcoma. The survival rate of patients with osteosarcoma has improved as a result of better adjuvant chemotherapeutic regimens [1–3]. There are many other factors, however, that have been shown to influence the prognosis of this disease, among them the patient’s age, site and size of the lesion, chemotherapeutic regimens, and surgical procedures [4–9]. We recently reviewed all cases of conventional osteosarcoma treated at Chiba Cancer Center, and analyzed the clinical prognostic factors of this disease.