Selenium and genotypes as marker of risk in BRCA1 mutation carriers

Material and methods A group of 50 newly diagnosed breast and/or ovarian cancer patients carrying BRCA1 mutation was analyzed by exon-by-exon sequencing of 3 genes (GPX1, GPX4, TXNRD2) coding selenoproteins. Simultaneously a nested case-control study of 39 women with breast cancer and 7 women with ovarian cancer (blood samples for all affected carriers were collected before treatment) and 92 controls matched 1 to 2 cases has been conducted and changes detected by sequencing have been analyzed. Additional case – control studies were performed on 45 pairs 1:2 matched for GPX1 (rs1050450). All cases and controls were matched for age at enrolment, past history of breast cancer and oophorectomy. All these patients were carriers of one of three Polish founder BRCA1 mutation. In these patients plasma selenium level has been determined. The following techniques for laboratory analyses have been applied: a) sequencing on (ABI310), b) SimpleProbe or Taqmqan analysis (a melting-curve genotyping with fluorescence-labeled probes based on the LightCycler 480 System (Roche Applied Science)), c) determination of selenium concentration in plasma using atomic absorption spectrometer AAnalyst600 (Perkin Elmer).