Makoto Emori

SYT-SSX breakpoint peptide vaccines in patients with synovial sarcoma: A study from the Japanese Musculoskeletal Oncology Group†

In the present study, we evaluated the safety and effectiveness of SYT‐SSX‐derived peptide vaccines in patients with advanced synovial sarcoma. A 9‐mer peptide spanning the SYT‐SSX fusion region (B peptide) and its HLA‐A*2402 anchor substitute (K9I) were synthesized. In Protocols A1 and A2, vaccines with peptide alone were administered subcutaneously six times at 14‐day intervals. The B peptide was used in Protocol A1, whereas the K9I peptide was used in Protocol A2. In Protocols B1 and B2, the peptide was mixed with incomplete Freunds adjuvant and then administered subcutaneously six times at 14‐day intervals. In addition, interferon‐α was injected subcutaneously on the same day and again 3 days after the vaccination. The B peptide and K9I peptide were used in Protocols B1 and B2, respectively. In total, 21 patients (12 men, nine women; mean age 43.6 years) were enrolled in the present study. Each patient had multiple metastatic lesions of the lung. Thirteen patients completed the six‐injection vaccination schedule. One patient developed intracerebral hemorrhage after the second vaccination. Delayed‐type hypersensitivity skin tests were negative in all patients. Nine patients showed a greater than twofold increase in the frequency of CTLs in tetramer analysis. Recognized disease progression occurred in all but one of the nine patients in Protocols A1 and A2. In contrast, half the 12 patients had stable disease during the vaccination period in Protocols B1 and B2. Of note, one patient showed transient shrinkage of a metastatic lesion. The response of the patients to the B protocols is encouraging and warrants further investigation.

High expression of CD109 antigen regulates the phenotype of cancer stem-like cells/cancer-initiating cells in the novel epithelioid sarcoma cell line ESX and is related to poor prognosis of soft tissue sarcoma.

Epithelioid sarcoma (ES) is a relatively rare, highly malignant soft tissue sarcoma. The mainstay of treatment is resection or amputation. Currently other therapeutic options available for this disease are limited. Therefore, a novel therapeutic option needs to be developed. In the present study, we established a new human ES cell line (ESX) and analyzed the characteristics of its cancer stem-like cells/cancer-initiating cells (CSCs/CICs) based on ALDH1 activity. We demonstrated that a subpopulation of ESX cells with high ALDH1 activity (ALDHhigh cells) correlated with enhanced clonogenic ability, sphere-formation ability, and invasiveness in vitro and showed higher tumorigenicity in vivo. Next, using gene expression profiling, we identified CD109, a GPI-anchored protein upregulated in the ALDHhigh cells. CD109 mRNA was highly expressed in various sarcoma cell lines, but weakly expressed in normal adult tissues. CD109-positive cells in ESX predominantly formed spheres in culture, whereas siCD109 reduced ALDH1 expression and inhibited the cell proliferation in vitro. Subsequently, we evaluated the expression of CD109 protein in 80 clinical specimens of soft tissue sarcoma. We found a strong correlation between CD109 protein expression and the prognosis (P = 0.009). In conclusion, CD109 might be a CSC/CIC marker in epithelioid sarcoma. Moreover, CD109 is a promising prognostic biomarker and a molecular target of cancer therapy for sarcomas including ES.

Fibroblasts induce expression of FGF4 in ovarian cancer stem-like cells/cancer-initiating cells and upregulate their tumor initiation capacity.

Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are defined as a small population of cells within cancer that contribute to cancer initiation and progression. Cancer-associated fibroblasts (CAFs) are stromal fibroblasts surrounding tumor cells, and they have important roles in tumor growth and tumor progression. It has been suggested that stromal fibroblasts and CSCs/CICs might mutually cooperate to enhance their growth and tumorigenic capacity. In this study, we investigated the effects of fibroblasts on tumor-initiating capacity and stem-like properties of ovarian CSCs/CICs. CSCs/CICs were isolated from the ovarian carcinoma cell line HTBoA as aldehyde dehydrogenase 1 high (ALDH1high) population by the ALDEFLUOR assay. Histological examination of tumor tissues derived from ALDH1high cells revealed few fibrous stroma, whereas those derived from fibroblast-mixed ALDH1high cells showed abundant fibrous stroma formation. In vivo tumor-initiating capacity and in vitro sphere-forming capacity of ALDH1high cells were enhanced in the presence of fibroblasts. Gene expression analysis revealed that fibroblast-mixed ALDH1high cells had enhanced expression of fibroblast growth factor 4 (FGF4) as well as stemness-associated genes such as SOX2 and POU5F1. Sphere-forming capacity of ALDH1high cells was suppressed by small-interfering RNA (siRNA)-mediated knockdown of FGFR2, the receptor for FGF4 which was expressed preferentially in ALDH1high cells. Taken together, the results indicate that interaction of fibroblasts with ovarian CSCs/CICs enhanced tumor-initiating capacity and stem-like properties through autocrine and paracrine FGF4-FGFR2 signaling.

Autologous CTL response against cancer stem-like cells/cancer-initiating cells of bone malignant fibrous histiocytoma

Malignant fibrous histiocytoma (MFH) of the bone is an aggressive tumor with high rates of local recurrence and metastasis. The development of novel therapeutic approaches is critical to improve the prognosis of patients with MFH. We reported previously that the side population (SP) cells of the MFH2003 bone MFH cell line have the characteristics of cancer stem‐like cells (CSC)/cancer‐initiating cells. In the present study, to establish immunotherapy targeting CSC, we analyzed cell surface immune molecules on SP cells of the MHF2003 cell line, as well as autologous CTL responses against these SP cells in the tumor microenvironment and peripheral circulating lymphocytes, using autologous tumor‐infiltrating lymphocytes and autologous CTL clones derived from peripheral blood, respectively. We found that the SP cells expressed human leukocyte antigen (HLA) Class I molecules on the cell surface. The autologous tumor‐infiltrating lymphocyte line TIL2003 recognized both the SP and main population cells of the MFH2003 cell line. Next, we induced the CTL clone Tc4C‐6 by mixed lymphocyte tumor cell culture using autologous peripheral blood mononuclear cells and freshly isolated SP cells, followed by a limiting dilution procedure. The Tc4C‐6 clone showed specific cytotoxicity against the SP cells. Moreover, the cytotoxicity against SP cells was blocked by the anti‐HLA Class I antibody W6/32. In conclusion, the findings of the present study support the idea that CSC of bone MFH are recognized by autologous CTL in the tumor microenvironment and peripheral circulating lymphocytes. Thus, CTL‐based immunotherapy could target CSC of bone sarcoma to help prevent tumor recurrence. (Cancer Sci 2011; 102: 1443–1447)

Diagnostic utility of FOSB immunohistochemistry in pseudomyogenic hemangioendothelioma and its histological mimics

BackgroundPseudomyogenic hemangioendothelioma (PHE) is an unusual vascular tumor of intermediate malignancy that rarely metastasizes and tends to arise in the lower limbs of young adults and children. Histologically, PHE shows fascicular proliferation of eosinophilic spindle cells and/or epithelioid cells showing “pseudomyogenic” morphology. Immunohistochemically, PHE is usually positive for vimentin, cytokeratin, CD31 and ERG.MethodWe examined FOSB immunohistochemistry (IHC) in 27 cases consisting of 4 PHE and its histologic mimics including 6 epithelioid hemangioendotheliomas (EHE), 8 angiosarcomas (AS), 4 Kaposi sarcomas (KS) and 5 epithelioid sarcomas (ES). In addition, we performed IHC of CAMTA1 which has recently been established as a useful marker of EHE. We elucidated the diagnostic utility of FOSB IHC in the differential diagnosis of PHE and its histological mimics and also examined the usefulness of FOSB and CAMTA1 IHC combination in the differential diagnosis of the tumors.ResultsIHC revealed diffuse and strong FOSB expression in all PHE cases, while the other tumor types demonstrated limited, weak or no FOSB expression. All EHE cases exhibited diffuse and moderate to strong expression of CAMTA1. All tumor types except for EHE showed limited, weak or no CAMTA1 reactivity.ConclusionsDiffuse and strong FOSB expression was specific for PHE in the current series and FOSB IHC is an effective tool for differentiating between PHE and its histological mimics. Moreover, the combination of FOSB and CAMTA1 IHC is useful for distinguishing PHE from EHE.

Diagnostic utility of NCOA2 fluorescence in situ hybridization and Stat6 immunohistochemistry staining for soft tissue angiofibroma and morphologically similar fibrovascular tumors

Soft tissue angiofibroma (STA), a recently suggested new histologic entity, is a benign fibrovascular soft tissue tumor composed of bland spindle-shaped tumor cells with abundant collagenous to myxoid stroma and branching small vessels. The lesion has a characteristic AHRR-NCOA2 fusion gene derived from chromosomal translocation of t(5;8)(p15;q13). However, morphologically similar tumors containing abundant fibrovascular and myxoid stroma can complicate diagnosis. We designed an original DNA probe for detecting NCOA2 split signals on fluorescence in situ hybridization (FISH) and estimated its utility with 20 fibrovascular tumors: 4 each of STAs, solitary fibrous tumors (SFTs), and cellular angiofibromas and 3 each of low-grade myxofibrosarcomas, myxoid liposarcomas, and low-grade fibromyxoid sarcomas. We also performed FISH for 13q14 deletion and immunohistochemistry (IHC) staining for estrogen receptor, progesterone receptor, retinoblastoma protein, and MUC-4 expression. Furthermore, IHC for Stat6 was conducted in the 20 cases analyzed by FISH and in an additional 26 SFTs. We found moderate to strong nuclear Stat6 expression in all SFTs but no expression in the other tumors. Both estrogen receptor and progesterone receptor expressions were observed in STAs, SFTs, and cellular angiofibromas. Expression of retinoblastoma protein was found in less than 10% of cells in all tumor types except myxoid liposarcoma. The low-grade fibromyxoid sarcomas were strongly positive for MUC-4. All STAs showed NCOA2 split signals on FISH. All tumors, regardless of histologic type, had 13q14 deletion. The NCOA2 FISH technique is a practical method for confirming STA diagnosis. The combination of NCOA2 FISH and Stat6 IHC proved effective for the differential diagnosis of STA, even when using small biopsy specimens.

Pre-operative Selective Arterial Embolization as a Neoadjuvant Therapy for Proximal Humerus Giant Cell Tumor of Bone: Radiological and Histological Evaluation

The management of giant cell tumor of the proximal humerus that extends to the joint is challenging. Here, we report a case of proximal humerus giant cell tumor with cortical bone destruction extending to the shoulder joint. Pre-operative selective arterial embolization induced peripheral tumor ossification. Subsequently, the lesion was removed by intralesional curettage, and the cavity was filled with cement. Macroscopically, the inner wall of the cavity was found to be lined with a thick fibrous membrane. Histologically, massive fibrosis and resultant remodeling of the destroyed cortical bone were induced, which was consistent with the peripheral ossification on the plain radiograph. We believe that selective arterial embolization can be an effective neoadjuvant therapy for giant cell tumors of the extremities, especially for tumors with large cortical defects or joint involvement.

Surgery With Vascular Reconstruction for Soft-Tissue Sarcomas in the Inguinal Region: Oncologic and Functional Outcomes

BACKGROUND Treatment of soft-tissue sarcomas involving the inguinal region remains challenging because of difficulties in achieving wide surgical margins due to anatomical features. The study aimed to analyze the oncologic and functional outcomes of wide resection with vascular reconstruction for inguinal soft-tissue sarcomas. METHODS Three men and seven women were treated for inguinal soft-tissue sarcomas by wide surgical resection with vascular reconstruction. RESULTS Arteries and veins were replaced in nine patients, and artery replacement alone was carried out in one patient. Femoral nerve resections were performed in six patients. One patient and five patients developed local recurrence and distant metastases, respectively. Limb salvage was achieved in 9 of 10 patients (90%). Six patients and one patient developed vascular (arterial graft occlusion [n = 1], lymphedema [n = 5]) and nonvascular (hematoma [n = 1]) complications, respectively. Five-year arterial primary patency was 77%. Five-year disease-free and overall survival rates were 45% and 77%, respectively. Functional outcome scores at latest follow-up averaged 87.5% for Musculoskeletal Tumor Society 1993. CONCLUSIONS En-bloc resection of major critical structures along with tumor and vascular reconstructions using synthetic grafts is a feasible option in limb salvage surgery for inguinal soft-tissue sarcomas.

Prognostic impact of CD109 expression in myxofibrosarcoma.

CD109, a TGF‐β co‐receptor, is reported to be preferentially expressed during the early stages of tumorigenesis in several carcinoma types. Myxofibrosarcoma is one of the most common soft‐tissue sarcomas found in elderly patients. This study aimed to elucidate the impact of CD109 expression in myxofibrosarcoma on prognosis and recurrence.

NUTM2A-CIC fusion small round cell sarcoma: a genetically distinct variant of CIC-rearranged sarcoma

CIC-rearranged sarcoma is a new entity of undifferentiated small round cell sarcoma characterized by chimeric fusions with CIC rearrangement. We report a NUTM2A-CIC fusion sarcoma in a 43-year-old woman who died of rapidly progressive disease. Histologic analysis revealed multinodular proliferation of small round tumor cells with mild nuclear pleomorphism. The sclerotic fibrous septa separated the tumor into multiple nodules. Immunohistochemistry showed that the tumor cells were diffusely positive for vimentin, focally positive for cytokeratin, and negative for CD99 and NKX2.2. Tumor cells were also negative for ETV4, which was recently identified as a specific marker for CIC-rearranged sarcoma. High-throughput RNA sequencing of a formalin-fixed, paraffin-embedded clinical sample unveiled a novel NUTM2A-CIC fusion between NUTM2A exon 7 and CIC exon 12, and fluorescence in situ hybridization identified CIC and NUTM2A split signals. This case shared several clinicopathological findings with previously reported CIC-rearranged cases. We recognized the tumor as a genetically distinct variant of CIC-rearranged sarcomas with a novel NUTM2A-CIC fusion.