Features of the Copy Number Variation of Certain Genes in Tumor Cells in Patients with Serous Ovarian Adenocarcinoma.

Abstract

We analyzed the peculiarities of the copy number variation of genes that regulate apoptosis, DNA repair, cell proliferation, metabolism, and estrogen reception in tumor and normal cells of high-grade and low-grade serous adenocarcinoma of the ovaries. Using real-time qPCR method, the relative copy number of 34 genes (BAX, BCL2, TP53, MDM2, CASP9, CASP3, CASP7, CASP8, PRKCI, SOX2, OCT4, PIK3, PTEN, C-MYC, SOX18, AKT1, NOTCH1, BRCA1, BRCA2, EXO1, SCNN1A, KRAS, EGFR, BRAF, CYP1A1, CYP1A2, CYP1B1, CYP19A, ESR1, ESR2, GPER, STS, SULT1A, and SULT1E1) was determined in normal and tumor cells of the ovaries extracted by contactless capture laser microsection from FFPE-blocks of 200 patients. The most typical molecular markers of ovarian serous adenocarcinoma cells were identified: copy number of PIK3CA, BCL2, BAX, CASP3, and CASP8 genes. Based on the differences in the gene copy number variation, two molecular subtypes of serous adenocarcinoma were identified, corresponding to two histological subtypes: high-grade (MDM2, SOX2, ESR1, CYP1B1, SULT1E1, TP53, BRCA2) and low-grade (PIK3CA, PTEN, BCL2, BAX, and CASP3). Each of these subtypes was also characterized by molecular heterogeneity and can be subdivided into several subgroups: 3 subgroups for high-grade and 4 subgroups for low-grade serous adenocarcinoma. These findings extend our understanding of the molecular mechanisms of carcinogenesis in the ovarian tissue, confirm molecular difference between the two histological subtypes of serous adenocarcinoma probably underlying their different clinical course.