CYP3A4 and breast carcinoma: This fact can be explained by the excess of the CYP3A4*1B gene homozygous variant or by the high frequency of the wild variant when compared with that of the polymorphism, although this hypothesis has not been clearly discussed in the literature.2, 18, 19, 20, 21, 22 Hereditary predisposition to breast cancer significantly influences the screening and follow-up of women at high risk of developing the disease.