Given the transmission pattern of VNTR, the uncertainty regarding the role of NHEJ in familial breast cancer, the presence of VNTR polymorphisms in the XRCC5 promoter, and the association of VNTR polymorphisms with sporadic cancer, we hypothesized that VNTR in the XRCC5 promoter could be involved in familial breast cancer. This evidence concerns the gene XRCC5 and breast cancer.