Gene expression data of ovarian clear cell carcinoma from Singapore

Ovarian clear cell carcinoma (OCCC) is an epithelial ovarian cancer (EOC) histology having distinct pathology, biology, and molecular footprints. OCCC is chemo-resistant and has the worst stage-adjusted prognosis amongst EOC. Yet, treatment for OCCC patients is no different than other EOC. As OCCC incidence rate has significantly increase in recent decades, it is critical to find OCCC-tailored therapeutic. However, majority of EOC gene expression molecular subtypes (GEMS) studies for personalized medicine focused on the high grade serous histology, and studies in OCCC GEMS were of small sample size. Using more than 200 OCCC gene expression profiles, we identified two OCCC subtypes: EpiCC—epithelial-like, early stage, good prognosis, relative higher rate of gene mutations in SWI/SNF complex; and MesCC—mesenchymal-like, late stage, and poor prognosis. The differential prognosis between EpiCC and MesCC could be observed as early as stage IC. Genetic, copy number and transcriptome profiling showed that both EpiCC and MesCC carried OCCC-associated aberrations. The EpiCC and MesCC are reproducible in validation cohorts and OCCC cell lines. Cell lines assays showed that MesCC is more proliferative and more anoikis resistant than EpiCC. Both EpiCC and MesCC are resistant to cisplatin. Applying the OCCC subtypes to TCGA 534 renal clear cell carcinoma indicated interoperability of the subtyping scheme, and revealed preferential response of EpiCC to sorafenib, and MesCC to bevacizumab. The EpiCC and MesCC classification shows promise in prognostication utility especially for stage IC OCCC patients, and warrants further investigation for subtype-tailored treatment regimen. Frozen archival epithelial ovarian cancer tumors samples of clear cell histology from Department of Obstetrics & Gynecology, National University of Singapore dated from 2006 to 2014 were collected and subjected to microarray analysis.