Takeaki Ishii

Prognostic significance of AKT/mTOR and MAPK pathways and antitumor effect of mTOR inhibitor in NF1-related and sporadic malignant peripheral nerve sheath tumors

Purpose: Malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with poor prognosis. MPNSTs occur frequently in patients with neurofibromatosis type 1 (NF1), in which NF1 gene deficiency leads to Ras hyperactivation. Ras activation causes the subsequent activation of the AKT/mTOR and Raf/MEK/ERK pathways and regulates cellular functions. However, the activation profiles of the AKT/mTOR and MAPK pathways in MPNSTs are poorly understood. The purposes of this study are to examine the correlation between the activation of these pathways and clinicopathologic or prognostic factors and to identify candidate target molecules in MPNST. Moreover, we assessed the antitumor effects of the inhibitor of candidate target. Experimental Design: Immunohistochemistry was conducted to evaluate the activation profiles of AKT/mTOR and MAPK pathways using 135 tumor specimens. Immunohistochemical expressions were confirmed by Western blotting. Then, an in vitro study was conducted to examine the antitumor effect of the mTOR inhibitor on MPNST cell lines. Results: Phosphorylated-AKT (p-AKT), p-mTOR, p-S6RP, p-p70S6K, p-4E-BP1, p-MEK1/2, and p-ERK1/2 expressions were positive in 58.2%, 47.3%, 53.8%, 57.1%, 62.6%, 93.4%, and 81.3% of primary MPNSTs, respectively. Positivity for each factor showed no difference between NF1-related and sporadic MPNSTs. Univariate prognostic analysis revealed that p-AKT, p-mTOR, and p-S6RP expressions were associated with poor prognosis. Furthermore, activation of each p-mTOR and p-S6RP was an independent poor prognostic factor by multivariate analysis. mTOR inhibition by Everolimus showed antitumor activity on MPNST cell lines in vitro. Conclusion: mTOR inhibition is a potential treatment option for both NF1-related and sporadic MPNSTs. Clin Cancer Res; 19(2); 450–61. ©2012 AACR.

Ossifying fibromyxoid tumor presenting EP400-PHF1 fusion gene.

Ossifying fibromyxoid tumor is a rare soft tissue tumor of borderline malignancy and uncertain differentiation. Recently, a novel fusion gene, EP400-PHF1, was discovered in ossifying fibromyxoid tumor; however, its relation to this type of tumor has been uncertain because the EP400-PHF1 fusion gene has been successfully detected in only 1 case. We present an ossifying fibromyxoid tumor case with the EP400-PHF1 fusion gene detected by reverse transcriptase polymerase chain reaction, along with compatible cytogenetic data showing a t(6;12)(p21;q24.3) translocation. Our results suggest that the EP400-PHF1 fusion gene is a reproducible finding in ossifying fibromyxoid tumor.

Prognostic Impact of the Activation Status of the Akt/mTOR Pathway in Synovial Sarcoma

The Akt/mammalian target of rapamycin (mTOR) pathway, downstream from phosphatidylinositol 3‐kinase (PI3K), mediates cell survival and proliferation. Although this pathway reportedly contributes to the progression of synovial sarcoma, its prognostic impact has not been clarified.

Histological and immunohistochemical characteristics of undifferentiated small round cell sarcomas associated with CIC-DUX4 and BCOR-CCNB3 fusion genes

CIC-DUX4 and BCOR-CCNB3 fusion-gene-associated small round cell sarcomas account for a proportion of pediatric small round cell sarcomas, but their pathological features have not been sufficiently clarified. We reviewed a large number of soft tissue tumors registered at our institution, retrieved the cases of unclassified tumors with a small round cell component, and subjected them to histopathological, immunohistochemical, and gene profile analysis. We reviewed 164 cases of unclassified tumors with a small round cell component and analyzed them by RT-PCR and FISH. Tumors positive for a specific fusion-gene were also subjected to histopathological and immunohistochemical examinations. We identified 16 cases of BCOR-CCNB3/CIC-associated (CIC-DUX4 or CIC gene rearrangement-positive) sarcomas. These included seven BCOR-CCNB3 sarcomas and nine CIC-associated sarcomas. Heterogeneous elements included a myxoid spindle cell component in three BCOR-CCNB3 sarcomas and an epithelioid cell component in two CIC-associated sarcomas (one CIC-DUX4-positive and one CIC-DUX4-negative sarcomas). Mitotic activity was low in both heterogeneous components. By immunohistochemistry, in seven BCOR-CCNB3 sarcomas expression of EMA was positive in two cases, of p63 in three, of CD56 in six, of TLE1 in seven, of NKX2.2 in two, of CCNB3 in seven, and of BCOR in six cases (one case could not be tested for BCOR). In nine cases of CIC-associated sarcoma, CD56 was expressed in five, alpha-smooth muscle actin in one, ERG in three, and CD99, WT1 and TLE1 each in eight cases. Both sarcoma types showed not only a small round cell component, but also a myxoid/epithelioid component with low mitotic activity.

Cancer‐testis antigens PRAME and NY‐ESO‐1 correlate with tumour grade and poor prognosis in myxoid liposarcoma

Myxoid liposarcoma is the second most common liposarcoma. Although myxoid liposarcoma is relatively chemosensitive and thus a good candidate for chemotherapy, cases with relapsed or metastatic disease still have poor outcome. Here, we performed a gene microarray analysis to compare the gene expression profiles in six clinical myxoid liposarcoma samples and three normal adipose tissue samples, and to identify molecular biomarkers that would be useful as diagnostic markers or treatment targets in myxoid liposarcoma. This showed that the cancer‐testis antigen PRAME was up‐regulated in myxoid liposarcoma. We then performed immunohistochemical, western blotting and real‐time polymerase chain reaction analyses to quantify the expression of PRAME and another cancer‐testis antigen, NY‐ESO‐1, in clinical samples of myxoid liposarcoma (n = 93), dedifferentiated (n = 46), well‐differentiated (n = 32) and pleomorphic liposarcomas (n = 14). Immunohistochemically, positivity for PRAME and NY‐ESO‐1 was observed in 84/93 (90%) and 83/93 (89%) of the myxoid liposarcomas, and in 20/46 (43%) and 3/46 (7%) of the dedifferentiated, 3/32 (9%) and 1/32 (3%) of the well‐differentiated and 7/14 (50%) and 3/21 (21%) of the pleomorphic liposarcomas, respectively. High immunohistochemical expression of PRAME and/or NY‐ESO‐1 was significantly correlated with tumour diameter, the existence of tumour necrosis, a round‐cell component of >5%, higher histological grade and advanced clinical stage. High PRAME and NY‐ESO‐1 expression correlated significantly with poor prognosis in a univariate analysis. The myxoid liposarcomas showed significantly higher protein and mRNA expression levels of PRAME and NY‐ESO‐1 (CTAG1B) than the other liposarcomas. In conclusion, PRAME and NY‐ESO‐1 (CTAG1B) were expressed in the vast majority of myxoid liposarcomas, and their high‐level expression correlated with tumour grade and poor prognosis. Our results support the potential use of PRAME and NY‐ESO‐1 as ancillary parameters for differential diagnosis and as prognostic biomarkers, and indicate that the development of immunotherapy against these cancer‐testis antigens in myxoid liposarcoma would be warranted.

Physical performance deterioration of temporary housing residents after the Great East Japan Earthquake

Disaster has a negative impact on health conditions, especially on those of temporary housing residents. Health status has a close relationship with physical activity and performance. However, few reports have assessed physical performance among residents living in temporary housing. In this study, we compared physical capabilities between the elderly who evacuated to temporary housing and those who stayed in their own homes after the Great East Japan Earthquake. Subjects were recruited from those over 65 years of age who participated in the medical check-ups for temporary housing residents (TH group) or check-ups for residents of downtown areas (control group) in Soma City, Fukushima, in 2012. The subjects underwent grip strength, one-leg standing (OLS), and timed up and go tests (TUG). In total, 1890 participants were recruited. The TH group showed significantly stronger grip strength than that of the control group. On the other hand, the TH group showed weaker standing stability, according to decreased OLS and increased TUG scores. We revealed that standing stability was impaired among elderly temporary housing residents 1.5 years after the disaster. Disaster responders should take into account the health risks associated with living in temporary housing.

Conventional spindle cell–type malignant peripheral nerve sheath tumor arising in a sporadic schwannoma

Malignant peripheral nerve sheath tumor is a malignant tumor showing nerve sheath differentiation. Approximately one-half of malignant peripheral nerve sheath tumors arise from a benign peripheral nerve sheath tumor, which is commonly a neurofibroma in patients with neurofibromatosis type 1. Malignant peripheral nerve sheath tumor arising in a sporadic schwannoma of soft tissue is extremely rare. In this condition, malignant cells usually show epithelioid morphology, meeting the diagnostic criteria for epithelioid malignant peripheral nerve sheath tumor. Here, we present an extraordinary case of spindle cell-type malignant peripheral nerve sheath tumor arising in a schwannoma on the back of a 58-year-old woman without neurofibromatosis. The malignant component showed hypercellular spindle cell proliferation with high mitotic activities; in contrast, the benign component showed hypocellular spindle cell proliferation in a palisading pattern and with Verocay bodies. Immunohistochemical S-100 protein staining showed a clear contrast between the malignant (negative) and benign (positive) components, which was useful for differentiating cellular schwannoma. Recognizing this rare condition is helpful in the pathologic diagnosis of schwannoma showing cellular proliferation in part.

Phosphorylation of signal transducer and activator of transcription 3 in soft tissue leiomyosarcoma is associated with a better prognosis

Signal transducer and activator of transcription (STAT) 3 mediates a broad range of biological processes, including cell survival and proliferation, and STAT3 has generally been regarded as a pro‐oncogenic transcription factor. We investigated the phosphorylation status of STAT3 and the protein expression of the suppressor of cytokine signaling 3 (SOCS3) by immunohistochemistry in 145 formalin‐fixed, paraffin‐embedded samples of soft tissue leiomyosarcoma (LMS), including 129 primary tumors. Eight benign soft tissue smooth muscle tumors were also examined. Thirteen frozen LMS samples, which were paired with normal tissue samples, were assessed by Western blot analysis for the phosphorylation of STAT3 and SOCS3 expression. Immunohistochemical study showed that the phosphorylation of STAT3 was not a major event in LMS (37%). Moreover, phosphorylated STAT3 (pSTAT3) expression was significantly correlated with a better prognosis. Overexpression of SOCS3 was recognized in 52% of the cases and negatively correlated with pSTAT3 expression. Among the benign tumors, 63 and 25% were positive for pSTAT3 and SOCS3, respectively. Immunoblotting detected pSTAT3 in all tumor samples, but at lower levels than in non‐neoplastic tissue. SOCS3 was detected in 92% (12 out of 13) of tumor tissues, but in none of the normal tissues. Contrary to the previous investigations of many other malignant tumors, STAT3 was inactivated in most LMS cases, likely owing to SOCS3 overexpression. STAT3 might not contribute to the progression of soft tissue LMS, and the phosphorylation status of STAT3 has the potential to be a favorable prognostic marker of LMS.

Cancer-testis antigen expression in synovial sarcoma: NY-ESO-1, PRAME, MAGEA4, and MAGEA1

Synovial sarcoma (SS) is regarded as a relatively chemosensitive sarcoma, but the prognosis of advanced SSs remains poor. Here we identified highly expressed cancer-testis antigens that could be promising immunotherapy targets for SS, using a previously conducted cDNA microarray, and we assessed the clinicopathological or prognostic relationships of these antigens in SS. We compared the gene expression profiles of 11 SSs with those of 3 normal adipose tissues. Among the up-regulated cancer-testis antigens, we analyzed PRAME, MAGEA1, and MAGEA4 and another cancer-testis antigen (NY-ESO-1) together, by immunohistochemistry and real-time polymerase chain reaction in 108 SSs. Immunohistochemically, NY-ESO-1, PRAME, MAGEA4, and MAGEA1 were positive in 66 (61%), 93 (86%), 89 (82%), and 16 (15%) of 108 SSs, respectively, and 104 (96%) of 108 SSs showed the immunohistochemical expression of at least 1 of NY-ESO-1, PRAME, and MAGEA4. Moreover, the high expression of at least 1 of these 3 antigens was observed in 83% of the SSs. High expression of NY-ESO-1 and MAGEA4 was significantly correlated with the presence of necrosis and advanced clinical stage. The immunohistochemical expression of these cancer-testis antigens was not correlated with prognosis, but the coexpression of NY-ESO-1, PRAME, and MAGEA4 was significantly associated with adverse prognosis. The real-time polymerase chain reaction results were closely related to the immunohistochemical results: NY-ESO-1 (P = .0019), PRAME (P = .039), MAGEA4 (P = .0149), and MAGEA1 (P = .0766). These data support the potential utility of NY-ESO-1, PRAME, and MAGEA4 as immunotherapy targets and ancillary prognostic parameters, suggesting the possible benefit of the combined use of these cancer-testis antigens as an SS immunotherapy target.

Histological spectrum of angiofibroma of soft tissue: histological and genetic analysis of 13 cases

Angiofibroma of soft tissue (AFST) is a rare soft tissue neoplasm characterized by a fibroblastic cytomorphology and a prominent vascular structure. AFSTs possess a novel fusion gene, i.e. NCOA2–AHRR/AHRR–NCOA2 or GTF2I–NCOA2, providing a useful approach to diagnosing AFST. Morphologically, AFSTs span a wide spectrum, making diagnosis a challenge. The aim of this study was to review AFST cases and to report previously unknown histological features, which we confirmed by genetic analysis.