The current literature suggests also the following predictive factors for bilateral breast cancer development: BC familial history [7, 25, 27], BRCA gene mutations [38], HER-2/Neu positivity [39], overweight [40], lobular histology [3, 41], and metropolitan residence, being this last probably due to a better access to the mammographic screening [25]. The gene discussed is ERBB2; the disease is breast carcinoma.