Whereas, other genes have been proved involved in BC development solely in Africa such as APOBEC3A, APOBEC3B, ARID1B, NCOR1, SMAD4, MAP3K1, HER2, HER and RAD50 or only in Europe such as RAD51 [82–84], COMT [85, 86], CYP17 [86], MRE11A [61, 87], CYP19 [87] and MDM2 [88]. This evidence concerns the gene SMAD4 and breast cancer.