To assess the possibility that allelic imbalance of RAD51 expression may occur in breast cancer patients, we chose a common exonic SNP – exon 10 c.1020*+718G>A – as a marker of RAD51 gene expression, and we assessed four LCLs from individuals heterozygous for these variants using single nucleotide primer extension. This evidence concerns the gene RAD51 and breast carcinoma.