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Abstract In cancer genome analysis, identifying pathogenic alterations and assessing their effects on oncogenic processes is important. Although whole exome sequencing (WES) can effectively detect such changes, driver alterations could not be identified in 27.8% of the cases, according to a previous study. The objectives of the present study were to evaluate the utility of whole genome sequencing (WGS) and clarify its differences with WES in terms of driver alteration detection. For this purpose, WGS analysis was conducted on 177 driverless WES samples, selected from 5,480 fresh frozen samples derived from 5,140 Japanese patients with cancer. These samples were selected as primary tumor, both WES and transcriptome profiling were performed, estimated tumor content of ≥ 30%, and no driver alterations were identified by WES. WGS identified driver and likely driver alterations in 68.4 and 22.6% of the samples, respectively. The most frequent alteration type was oncogene amplification, followed by tumor suppressor gene deletion and small variants located outside the coding region. In the remaining 9.0% of samples, no such signals were identified; therefore, further investigations are required. The current study clearly demonstrated the role and utility of WGS in identifying genomic alterations that contribute to tumorigenesis.

Abstract Objective Pan‐cancer analysis across The Cancer Genome Atlas has revealed the molecular profiles of major types of carcinomas. High‐grade serous carcinomas (HGSCs) have been characterized; however, in ovarian cancer, the profile of carcinoma with minor histopathological changes remains unclear. This study aimed to perform the molecular profiling of rare malignant ovarian tumors, including non‐epithelial tumors (NETs; germ cell tumors and sex cord tumors) and clear cell carcinoma (CCC), to determine how they differ from the major HGSCs. Methods Sixty‐nine malignant ovarian tumors surgically resected at the Shizuoka Cancer Center between January 2014 and March 2019 were classified based on their histopathological types. The germline and somatic mutations in these carcinomas, including NETs, were determined using next‐generation sequencing. Gene expression analysis was performed to investigate the major pathways of drug resistance, which is a characteristic of CCC. Results NETs harbored copy‐neutral loss of heterozygosity, accompanied by a high homologous recombination deficiency score; germline mutations of PALB2 and BARD1 were identified in two patients with NET. In chemoresistant CCC, the epithelial‐mesenchymal transition pathway was activated regardless of ABC transporter expression. Conclusion This study revealed some genomic characteristics of rare malignant ovarian tumors, including NETs and CCC.

Abstract Background Microsatellite instability (MSI) is a key marker for predicting the response of immune checkpoint inhibitors (ICIs) and for screening Lynch syndrome (LS). Aim This study aimed to see the characteristics of cancers with high level of MSI (MSI-H) in genetic medicine and precision medicine. Methods This study analyzed the incidence of MSI-H in 1000 cancers and compared according to several clinical and demographic factors. Results The incidence of MSI-H was highest in endometrial cancers (26.7%, 20/75), followed by small intestine (20%, 3/15) and colorectal cancers (CRCs)(13.7%, 64/466); the sum of these three cancers (15.6%) was significantly higher than that of other types (2.5%)(P

Abstract Background Somatic PTEN mutation occurs in a proportion of ovarian endometrioid carcinomas. However, these cancers have seldom been reported in diseases associated with germline PTEN variants, such as Cowden syndrome (CS). Case presentation The present case was a 39-year-old woman with a left ovarian carcinoma who demonstrated a germline splice variant of PTEN (c.1026 + 1G > T) following genome-wide whole exome sequencing of her germline DNA. Histology of her resected tumor revealed endometrioid carcinoma of the same type as a right ovarian cancer resected eight years previously. These tumors showed null immunostaining for PTEN. She was genetically diagnosed with CS. Despite her clinical examinations had demonstrated several characteristic findings of CS, including mammary fibroma, esophageal and skin papilloma, colonic hamartoma, uterine myoma, and lipoma, the clinicians could not approach this diagnosis. Conclusion Ovarian endometrioid carcinoma is generally thought to develop from endometrial tissue menstruated from the uterus and implanted on the ovary. To date, ovarian cancers have not been listed as CS-related cancers; however, ovarian endometrioid cancer can have a potential association with CS in endometriosis cases.

Abstract Background The prevalence of brain metastases (BM) from uterine cancer has recently increased because of the improvement of overall survival (OS) of patients with uterine cancer due to its early detection and improved local control as a result of new effective treatments. However, little information is available regarding their clinical characteristics and prognosis, because oncologists have encountered BM from uterine cancer on rare occasions. Methods Records from 81 patients with uterine BM were collected from 10 institutes in Japan. These were used in a multi-institutional study to identify prognostic factors and develop a graded prognostic assessment (GPA) for patients with BM from uterine cancer. Results Median OS after the development of BM was 7 months (95% confidence interval, 4 to 10 months). Multivariate analysis revealed that there were survival differences according to the existence of extracranial metastases and number of BM. In the present uterine-GPA, a score of 0 was assigned to those patients with ≥5 BM and extracranial metastasis, a score of 2 was assigned to those patients with one to four BM or without extracranial metastasis, and a score of 4 was assigned to those patients with one to four BM and without extracranial metastasis. The median OS for patients with a uterine-GPA scores of 0, 2, and 4 was 3, 7, and 22 months, respectively. A survival analysis confirmed the presence of statistically significant differences between these groups (p