Kunio Iura

Tumour-associated macrophages correlate with poor prognosis in myxoid liposarcoma and promote cell motility and invasion via the HB-EGF-EGFR-PI3K/Akt pathways

Background:Myxoid liposarcoma (MLS) is the second most common subtype of liposarcoma, and metastasis occurs in up to one-third of cases. However, the mechanisms of invasion and metastasis remain unclear. Tumour-associated macrophages (TAMs) have important roles in tumour invasion, metastasis, and/or poor prognosis. The aim of this study was to investigate the relationship between TAMs and MLS.Methods:Using 78 primary MLS samples, the association between clinical prognosis and macrophage infiltration was evaluated by immunochemistry. The effects of macrophages on cell growth, cell motility, and invasion of MLS cell lines were investigated in vitro. In addition, clinicopathological factors were analysed to assess their prognostic implications in MLS.Results:Higher levels of CD68-positive macrophages were associated with poorer overall survival in MLS samples. Macrophage-conditioned medium enhanced MLS cell motility and invasion by activating epidermal growth factor receptor (EGFR), with the key ligand suggested to be heparin-binding EGF-like growth factor (HB-EGF). The phosphoinositide 3-kinase/Akt pathway was mostly involved in HB-EGF-induced cell motility and invasion of MLS. The expression of phosphorylated EGFR in MLS clinical samples was associated with macrophage infiltration. In addition, more significant macrophage infiltration was associated with poor prognosis even in multivariate analysis.Conclusions:Macrophage infiltration in MLS predicts poor prognosis, and the relationship between TAMs and MLS may be a new candidate for therapeutic targets of MLS.

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.

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.

Malignant solitary fibrous tumor with high-grade nuclear atypia: An alternate entity for the undetermined tumor group

Recently, a novel fusion transcript, NAB2-STAT6, and its variants have also been reported to be specific diagnostic markers for solitary fibrous tumors (SFTs). In this study, we validated the existence of the NAB2-STAT6 fusion gene in SFTs and examined its relation with the pathological features. Frozen samples from 9 tumors were assessed for fusion gene. The detected fusion genes exhibited large intron sequences and the insertion of unknown and previously unreported sequences. The fusion genes were not detected in the 2 malignant cases with high-grade nuclear atypia, nuclear pleomorphism and necrosis, that was confirmed by multiplex PCR method. In addition, 1 of the 2 NAB2-STAT6 fusion gene-negative tumors showed amplification of the MDM2 and CDK4 genes. It was suggested that a certain proportion of tumors previously diagnosed as malignant SFTs with high-grade nuclear atypia lacking NAB2-STAT6 should be categorized into a special subtype of SFT, which is genetically different from conventional SFTs, and which cannot be apparently distinguished from dedifferentiated liposarcoma or undifferentiated pleomorphic sarcoma.

Prognostic significance of FOXM1 expression and antitumor effect of FOXM1 inhibition in synovial sarcomas.

BackgroundSynovial sarcoma (SS) is a soft tissue sarcoma of unknown histogenesis. Most metastatic or unresectable cases are incurable. Novel antitumor agents and precise prognostication are needed for SS patients. The protein forkhead box M1 (FOXM1), which belongs to the FOX family of transcription factors, is considered to be an independent predictor of poor survival in many cancers and sarcomas, but the prognostic implications and oncogenic roles of FOXM1 in SS are poorly understood. Here we examined the correlation between FOXM1 expression and clinicopathologic and prognostic factors, and we investigated the efficacy of FOXM1 target therapy in SS cases.MethodsImmunohistochemical study of 106 tumor specimens was conducted to evaluate their immunohistochemical expression of FOXM1. An in vitro study examined the antitumor effect of the FOXM1 inhibitor thiostrepton and small interference RNA (siRNA) on two SS cell lines. We also assessed the efficacy of the combined use of doxorubicin (DOX) and thiostrepton.ResultsUnivariate and multivariate analyses revealed that FOXM1 expression was associated with poor prognosis in SS. The cDNA microarray analysis using clinical samples revealed that the expression of cell cycle-associated genes was correlated with FOXM1 expression. FOXM1 inhibition by thiostrepton showed significant antitumor activity on the SS cell lines in vitro. FOXM1 interruption by siRNA increased the chemosensitivity for DOX in both SS cell lines.ConclusionFOXM1 expression is a novel biomarker, and its inhibition is a potential treatment option for SS.

Soft tissue sarcomas: From a morphological to a molecular biological approach

Recently developed molecular genetic techniques have led to the elucidation of tumor‐specific genomic alterations and thereby the reclassification of tumor entities of soft tissue sarcoma. A solitary fibrous tumor‐mimicking tumor with the AHRR‐NCOA2 gene has been isolated as angiofibroma of soft tissue. As for small round cell sarcomas, novel fusion genes such as CIC‐DUX4 and BCOR‐CCNB3 have been identified in these tumor groups. SMARCB1/INI1 deficient tumors with round cell morphology are also expected to be reclassified in three types, based on the combination of their morphology and genotype. The identification of the MDM2 gene amplification in pleomorphic sarcomas has extended the entity of dedifferentiated liposarcoma (DDLS). Our recent molecular investigations elucidated candidates for novel therapeutic strategies. Activation of the Akt‐mTOR pathway was correlated with poor prognosis or tumor grade in spindle cell sarcomas including malignant peripheral nerve sheath tumor. In vitro and in vivo studies of transcription factor Forkhead Box M1 (FOXM1) demonstrated the close correlation between aggressive biological behavior or chemosensitivity and FOXM1 expression in synovial sarcoma, so far. Finally, in regard to the investigation of cancer‐testis antigens, myxoid/round cell liposarcoma and synovial sarcoma showed frequent and high expression of PRAME and NY‐ESO‐1.

Phosphorylation of STAT3 in Undifferentiated Pleomorphic Sarcoma Is Correlated with a Favorable Prognosis

Objective: The Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway plays a role in various biological processes. Phosphorylated STAT3 (p-STAT3) functions as a transcriptional factor, and suppressor of cytokine signaling 3 (SOCS3) is a potential inhibitor of STAT3. Here, we analyzed the status of the JAK-STAT pathway in undifferentiated pleomorphic sarcoma (UPS). Methods: We performed immunohistochemistry in 79 samples of UPS and Western blotting in 10 frozen samples. We also examined alterations in protein expression in the JAK-STAT pathway after the inhibition of phosphorylated Akt (p-Akt) or extracellular signal-regulated kinase (p-Erk) in vitro. Results: Immunohistochemically, p-STAT3 and SOCS3 were positive in 59.7 and 55.8%, respectively. Positivity for p-STAT3 was significantly correlated with a better prognosis (p = 0.0006) and negatively with SOCS3 expression (p = 0.0223). Positivity for SOCS3 was significantly correlated with a worse prognosis (p = 0.0001). Western blotting analysis revealed that p-STAT3 expression was lower in tumor than in normal tissue. In vitro results demonstrated that there was no detectable change in the expression of p-STAT3 regardless of the status of p-Akt or p-Erk. Conclusion: p-STAT3 may be a useful prognostic factor for UPS.

Expression of Forkhead box M1 in soft tissue leiomyosarcoma: Clinicopathologic and in vitro study using a newly established cell line.

Leiomyosarcoma (LMS) of soft tissue is a sarcoma with smooth‐muscle differentiation, and conventional chemotherapy does not improve its outcome. The application of novel antitumor agents and precise prognostication has been demanded. The expression of the protein Forkhead box M1 (FOXM1), a member of the FOX family, is considered an independent predictor of poor survival in many cancers and sarcomas. However, the expression status of FOXM1 in LMS is poorly understood. The purposes of this study were to examine the correlation between the expression of FOXM1 and clinicopathologic or prognostic factors and to clarify the efficacy of FOXM1 target therapy in LMS. We evaluated the immunohistochemical expressions of FOXM1 using 123 LMS tumor specimens. Univariate and multivariate survival analyses revealed that FOXM1 expression was associated with poor prognosis in LMS. An in vitro study was then carried out to examine the antitumor effect of a FOXM1 inhibitor (thiostrepton) and siRNA on a novel LMS cell line, TC616. We also assessed the efficacy of the combined use of doxorubicin and thiostrepton. Thiostrepton showed dose‐dependent antitumor activity and TC616 cells treated with the combination of thiostrepton and doxorubicin showed lower proliferation compared to those treated with either drug individually. FOXM1 interruption by siRNA decreased cell proliferation and increased chemosensitivity. In conclusion, FOXM1 has potential to be a therapeutic target for LMS.