Yutaka Takazawa

Modeling Alveolar Soft Part Sarcoma Unveils Novel Mechanisms of Metastasis

Alveolar soft part sarcoma (ASPS) is a slowly growing, but highly metastatic, sarcoma that affects adolescents and young adults. Its characteristic alveolar structure is constituted by tumor cell nests and an abundant vascular network that is responsible for metastatic activities at the initial stage. Here, we have generated a new ex vivo mouse model for ASPS that well recapitulates associated angiogenic and metastatic phenotypes. In mouse ASPS, the tumor cells frequently showed tumor intravasation, with the intravascular tumor cells presenting as organoid structures covered with hemangiopericytes, which is also observed in human ASPS. High expression of glycoprotein nmb (GPNMB), a transcriptional target of ASPSCR1-TFE3, was observed at the sites of intravasation. ASPS tumor cells also demonstrated enhanced transendothelial migration activity, which was inhibited by silencing of Gpnmb, indicating that GPNMB plays an important role in tumor intravasation, a key step in cancer metastasis. The present model also enabled the evaluation of TFE/MITF family transcription factor function, which demonstrated that ASPSCR1-TFEB possessed definitive albeit less marked oncogenic activity than that of ASPSCR1-TFE3. Collectively, our mouse model provides a tool to understand oncogenic, angiogenic, and metastatic mechanisms of ASPS. It also identifies important motifs within the ASPSCR1-TFE3 fusion protein and provides a platform for developing novel therapeutic strategies for this disorder. Cancer Res; 77(4); 897-907. ©2016 AACR.

CIC-DUX4 Induces Small Round Cell Sarcomas Distinct from Ewing Sarcoma

CIC-DUX4 sarcoma (CDS) or CIC-rearranged sarcoma is a subcategory of small round cell sarcoma resembling the morphological phenotypes of Ewing sarcoma (ES). However, recent clinicopathologic and molecular genetic analyses indicate that CDS is an independent disease entity from ES. Few ancillary markers have been used in the differential diagnosis of CDS, and additional CDS-specific biomarkers are needed for more definitive classification. Here, we report the generation of an ex vivo mouse model for CDS by transducing embryonic mesenchymal cells (eMC) with human CIC-DUX4 cDNA. Recipient mice transplanted with eMC-expressing CIC-DUX4 rapidly developed an aggressive, undifferentiated sarcoma composed of small round to short spindle cells. Gene-expression profiles of CDS and eMC revealed upregulation of CIC-DUX4 downstream genes such as PEA3 family genes, Ccnd2, Crh, and Zic1 IHC analyses for both mouse and human tumors showed that CCND2 and MUC5AC are reliable biomarkers to distinguish CDS from ES. Gene silencing of CIC-DUX4 as well as Ccnd2, Ret, and Bcl2 effectively inhibited CDS tumor growth in vitro The CDK4/6 inhibitor palbociclib and the soft tissue sarcoma drug trabectedin also blocked the growth of mouse CDS. In summary, our mouse model provides important biological information about CDS and provides a useful platform to explore biomarkers and therapeutic agents for CDS. Cancer Res; 77(11); 2927-37. ©2017 AACR.

MR Imaging of Secondary Massive Ovarian Edema Caused by Ovarian Metastasis from Appendiceal Adenocarcinoma

A 29-year-old woman presented to her physician with abdominal distention. Laboratory data showed slight anemia (Hb 11.1 g/dl) and elevation of CA125 (228.3 U/ml). Noncontrast MR revealed enlarged bilateral ovaries. The mass bodies showed hyperintensity whereas their peripheral areas showed lower intensity on T2-weighted images (T2WI, Figs. 1A and 1B). There were small, well-demarcated, round or oval areas of extremely hyperintensity along the periphery of the masses, suggesting spared follicles. Diffusionweighted images (b = 1000 s/mm2, Fig. 1C) indicated increased diffusion in the center of the masses, compared to the periphery. Contrast CT revealed twisted soft tissue with large vessels at the lateral portion of the right ovary (Fig. 1D), suggesting torsion. Therefore, we suspected the masses were massive ovarian edema (MOE) and ovarian torsion had driven the enlargement of the right ovary. However, expiratory laparotomy revealed a swollen appendix, peritoneal implants and enlarged ovaries without torsion. Histopathologically, the central part of the ovary consisted of signet ring cell carcinoma and stromal edema (Fig. 1E), whereas poorly differentiated adenocarcinoma and stromal proliferation were noted along the periphery. Several preserved follicles were also seen in the ovarian cortex as if massive ovarian edema. The histopathological diagnosis was primary appendiceal adenocarcinoma with metastatic involvement of both ovaries. Discussion

Tumor B7-H3 (CD276) Expression and Survival in Pancreatic Cancer

B7-H3 (CD276), a member of the family of immune modulators, orchestrates antitumor immunity. To date, only small-sized studies have examined the association of B7-H3 expression with survival in pancreatic cancer, yielding inconclusive results. We evaluated tumor B7-H3 expression in 150 consecutive patients with pancreatic ductal adenocarcinoma using immunohistochemistry. B7-H3 expression was positive (≥10% tumor cells) in 99 of 150 (66%) cases of pancreatic cancer. We classified the tumors into four groups depending on B7-H3 expression (negative, low, intermediate, and high) and found that higher B7-H3 expression was independently associated with lower disease-free survival (DFS; for high vs. negative B7-H3 expression: multivariable hazard ratio (HR) = 3.12; 95% confidence interval (CI) = 1.48–6.15; Ptrend = 0.0026). Furthermore, the association of B7-H3 expression with survival differed according to the pathological stage (p-stage) (Pinteraction = 0.048, between p-stages I–II and III–IV). The association of B7-H3 positivity with lower DFS was stronger in tumors with p-stage I–II (multivariable HR = 3.10, 95% CI = 1.75–5.69; P < 0.0001) than in those with p-stage III–IV (multivariable HR = 1.20, 95% CI = 0.67–2.28; P = 0.55). We demonstrated that tumor high B7-H3 expression is independently associated with poor survival in patients with pancreatic cancer and that this association is stronger in tumors with p-stage I–II than in those with p-stage III–IV. B7-H3 expression may be a useful prognostic biomarker for identifying aggressive early-stage pancreatic cancer.

Clinical management of the status of atypical endometrial cells using the descriptive reporting format for endometrial cytology

We aimed to develop and reinforce a clinical management regimen for atypical endometrial cell (ATEC) categories within the descriptive reporting format for endometrial cytology.

Successful Complete Response of Tumor Thrombus after Combined with Chemotherapy and Irradiation for Ewing Sarcoma

Pelvic Ewing sarcoma is associated with a worse prognosis. Thromboembolic events are relatively common in pediatric patients with cancers including sarcomas. We have presented a case of Ewing sarcoma arising from the left iliac bone with tumor thrombus of inferior vena cava (IVC) which was obtained complete response by both chemotherapy and irradiation. Magnetic resonance imaging (MRI) scan demonstrated that the tumor arising from the left iliac bone extended into the left side of sacral bone, suggesting the difficulty of surgical resection. Computed tomography (CT) revealed the existence of the tumor thrombus of IVC. We performed irradiation (31.2 Gy) and chemotherapy (combination of VCR, Act-D, IFM, and ADR). The tumor was controlled successfully, and the tumor thrombus of IVC has completely vanished. Four years after the treatment, coin lesion in the left upper lung appeared. Suspected of metastasis, segmental resection of the left upper lung was performed. Fourteen years after the surgery, the patient has been remained free of recurrence. It is clinically significant for surgeons to treat pelvic Ewing sarcoma with tumor thrombus.

Osteosarcoma arising in fibrous dysplasia, confirmed by mutational analysis of GNAS gene

Malignancy arising in fibrous dysplasia (FD) is rare. Approximately 100 cases have been reported so far, and osteosarcoma is the most common malignancy. We report a case of osteosarcoma in a 33-year-old Japanese man with monostotic FD of the right proximal femur from the age of 16 years. Histologically, relatively well-differentiated osteosarcoma was found in the FD lesion. Immunohistochemically, the FD was negative for p53 or MDM2, and the MIB-1 index was less than 1%, whereas the osteosarcoma was positive for both p53 and MDM2, and the MIB-1 index was up to 15%. The FD and osteosarcoma were negative for CDK4. Fluorescent in situ hybridization assay showed no amplification of the MDM2 gene, indicating that the osteosarcoma was a conventional osteosarcoma, not an intraosseous well-differentiated type. The original cell of malignancy in FD is unclear. Malignancy can be potentially derived from dysplastic cells in the area of the FD or cells in the adjacent normal tissues. GNAS gene mutation has recently been reported for fibrous dysplasia and the mutation is highly specific to fibrous dysplasia among fibro-osseous lesions including osteosarcoma. In this case, point mutations of GNAS were found in the FD and osteosarcoma but not in the adjacent normal tissues, suggesting that osteosarcoma was derived from the spindle cells of FD. This is the first report to clearly show that osteosarcoma is derived from the spindle cells in fibrous dysplasia (FD).

Variable Distribution of Pseudolobules in Ovarian Sclerosing Stromal Tumors: Utility of Diffusion-weighted Imaging for Differential Diagnosis

Sclerosing stromal tumors (SSTs) are rare benign sex cord– stromal tumors of the ovary. Distinguishing SST from other malignant ovarian tumors is crucial because SSTs affect adolescents and young adults (AYA) who require fertility preservation. Here, we present a case of SST with characteristic imaging findings and its correlating pathological findings. A 17-year-old girl with irregular menstruation visited our institution. No abnormalities were identified by physical and laboratory evaluations. T2-weighted MR images (T2WI; Fig. 1a) revealed a relatively hypointense solid mass affecting the left adnexa. This mass included multiple island-shaped areas surrounded by hypointense rims. These areas were indistinct on T1-weighted images (Fig. 1b). No signal voids were observed within or around the tumor. Compared to endometrium, islandsshaped areas appeared significantly hyperintense on diffusionweighted imaging (DWI) (Fig. 1c), and restricted diffusion on apparent diffusion coefficient (ADC) map (Fig. 1d). These areas were as strongly enhanced as myometrium from the early phase to the equivalent phase of dynamic contrast enhancement (DCE) (Fig. 1e). Therefore, we speculated these island-shaped area might correspond to pseudolobules, a pathological hallmark of the SST. The preoperative imaging diagnosis was SST. Macroscopically, the resected left ovarian tumor showed a multilobulated yellow cut surface. Histologically, cellular pseudolobules were separated by dense fibrous stroma (Fig. 2a). Dilated vessels were frequently observed in cellular areas (Fig. 2b). Immunohistochemically, tumor cells were α-inhibinpositive (Fig. 2c). The pathological diagnosis was SST. SST predominantly affects AYA in whom the most common symptom is irregular menstruation. Pathologically, SST is characterized by a pseudolobular structure comprising hypervascular cellular areas separated by edematous or fibrous hypocellular areas. Hypointense nodules against hyperintense stroma on T2WI and striking enhancement have been reported as characteristic MR findings of SST.1 Although the stroma was expected to exhibit marked hyperintensity on T2WI, it was nearly isointense to the pseudolobules in our case. Rich collagen fibers within the background stroma might decrease the background signal and reduce the distinct contour of the pseudolobules. Pseudolobules comprised abundant tumor cells with hypervascularity, whereas the stroma comprised fibrous areas with low cellularity. We could thus recognize pseudolobules from the striking enhancement and restricted diffusion areas on MR. Matsubayashi et al. reported early peripheral tumor enhancement with centripetal progression on DCE2 as the pseudolobules were typically located at the tumor margin. However, in our case, the pseudolobules were scattered throughout the tumor and appeared as island-shaped areas with marked enhancement. These findings suggest wide variation in the distribution of pseudolobules and extent of stromal edema and fibrosis. DWI may be a promising technique for distinguishing pseudolobules with abundant tumor cells from edematous or collagenous background. Therefore, we speculate there are variety of distribution of pseudolobules in ovarian SSTs. So we carefully differentiate metastatic ovarian tumors from SSTs, which may also contain scattered tumor nest with distinct margins.2,3 In conclusion, regardless of the distribution of pseudolobulation and extent of edematous or fibrous stroma, DWI and DCE are useful for visualizing pseudolobules with abundant tumor cells and can facilitate the diagnosis of SST.

A Case of Ovarian Metastasis from Microinvasive Adenosquamous Carcinoma of the Uterine Cervix

Background: Ovarian metastasis is rare in cases of early-stage uterine cervical cancer. For the patients with stage 1b cervical cancer, the incidences of ovarian metastasis were 0.22% of squamous cell carcinoma and 3.72% of adenocarcinoma. The safety of ovarian preservation is controversial for young women, although these women may find it important to preserve fertility. Case: A 36-year-old Japanese woman underwent a loop electrosurgical excision procedure for cervical adenosquamous carcinoma with invasion of 0.8 mm in depth and 1 mm in horizontal extent. She wished to preserve her fertility and was therefore followed up without additional treatments. Thirty months after the loop electrosurgical excision procedure, she had 10 cm-diameter ovarian tumors and underwent hysterectomy, bilateral salpingooophorectomy, appendectomy. This ovarian tumor was revealed to metastasis from cervical carcinoma. Conclusion: To our knowledge, this is first reported case of ovarian metastasis with microinvasive adenosquamous cell carcinoma. The pathological characteristics are important for prognosis: frequent small foci of invasion and high atypia.