To evaluate the contribution of RAD51 to sporadic prostate cancer, loss of heterozygosity (LOH) for chromosomal region 15q14-21.1 (RAD51locus) was determined and compared to LOH in 17q21.31 (BRCA1 locus) and 13q12.3-13.1 (BRCA2 region). The gene discussed is BRCA1; the disease is Familial prostate cancer.