Loss of heterozygosity and microsatellite instability at RAD52 and RAD54 loci in breast cancer.

This study was carried out to evaluate the loss of heterozygosity (LOH) and microsatellite instability (MSI) in breast cancer, in the 12p13.3 and 1p32 chromosomal regions where RAD52 and RAD54 genes are localized. Polymorphic markers D12S98, D12S1698 for RAD52 and D1S209, D1S411 for RAD54 were used. Relationships between LOH and clinicopathological parameters, i.e. tumor type and grade, patient's age, steroid receptors status and lymph node and distal metastases were assessed. For alleles frequency estimation 100 primary breast cancers were tested. DNA isolated from paraffin-embedded tissues and their matched blood samples were analyzed for PCR-based LOH and MSI by fluorescence-based DNA sequencing technology. In analyzed cases LOH was found in 14% and 11% of informative cases for D12S98 and D12S1698 markers, respectively and in 18% and 17% of informative cases for D1S209 and D1S411 markers, respectively. The highest frequency of MSI was identified at loci D12S98 (10%) and D1S209 (11%). Significant correlations between RAD52 and RAD54 regions with concomitant LOH and histological type and progesterone receptor status were observed. In the case of RAD54 further correlations with respect to tumor grade and the presence of distal metastases were noticed.