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Identification of novel therapeutics in pelvic high-grade serous carcinoma (HGSC) has been hampered by a paucity of actionable point mutations in target genes. The aim of the present study was to investigate the extent of amplification of the therapeutically targetable NSD3-CHD8-BRD4 pathway in pelvic HGSC, and to determine whether amplification is associated with worse prognosis. The Cancer Genome Atlas (TCGA) ovarian and endometrial cancer cohorts were retrospectively analyzed via online data-mining tools to test the association of NSD3, CHD8 and BRD4 genomic alterations with survival of pelvic HGSC patients. It was demonstrated that amplification of the NSD3-CHD8-BRD4 pathway in the ovarian HGSC cohort (observed in 18% of the cases, 88/489) was significantly associated with worse overall and progression-free survival compared with non-amplified cases. In addition, amplification of NSD3, CHD8 and BRD4 also occurred in 9% (21/232) of overall endometrial cancer TCGA cases, which was associated with worse overall survival. In the endometrial cancer TCGA cohort, NSD3, CHD8 and BRD4 amplification occurred specifically in the serous carcinoma (25%, 13/53) and 'serous-like' copy number high endometrial carcinoma (33%, 20/60) subgroups, compared with the polymerase e (0%, 0/17), microsatellite instability high (0%, 0/65) or low copy number (1%, 1/90) subgroups. These findings support the hypothesis that amplification of the NSD3-BRD4-CDH8 axis is frequent in pelvic HGSC of both ovarian and endometrial origin, and that this pathway is potentially targetable in a subset of HGSC patients. [ABSTRACT FROM AUTHOR]

High-grade serous carcinoma (HGSC) of the ovary is an aggressive and devastating neoplasm and the identification of novel therapeutic targets may result in a significant decrease in patient morbidity and mortality. Over the last few years, chromatin regulators have become attractive targets for cancer therapy. More specifically, bromodomain-containing protein 4 (BRD4), a protein that is associated with acetylated chromatin and transcriptional activation, has been shown to selectively regulate the transcription of key oncogenic drivers, such as CMYC, in several tumor types. The Cancer Genome Atlas (TCGA) project has molecularly characterized the genome of ovarian serous carcinomas, which enabled us to study the association of genomic alterations of BRD4 with patient survival and clinicopathological characteristics. Our analysis using clinical and genomic data from the TCGA ovarian carcinoma samples revealed that somatic amplification of BRD4 (observed in 12% of the cases) was correlated with increased BRD4 mRNA levels and is significantly associated with worse overall and progression-free survival compared to wild-type cases. These findings support the hypothesis that future studies and trials investigating newly developed BRD4 inhibitors are required in a subset of patients with ovarian HGSC. [ABSTRACT FROM AUTHOR]