A study that included 275 Mexican women enrolled in the Ella Binational Breast Cancer Study reported that the T allele of the c.3435C>T polymorphism located in exon 26 of the ABCB1 gene was an important risk factor for breast cancer in premenopausal women and specifically for the TNBC subtype [106]. The gene discussed is ABCB1; the disease is breast cancer.