Total PCBs associated with AREG, CYP19A1, ESR2, FOS, KRAS and STC2 genes; PCB 126 associated with AREG, CYP19A1, and STC2 genes and PCB 15 associated with CYP19A1, EGFR, ESR2, FOS, and IGF1 genes overlapped with 17β-estradiol, breast cancer, and endometriosis (Table 2, Table 6 and Table 7). This evidence concerns the gene KRAS and breast cancer.