CYP2E1 and breast carcinoma: Of all the selected articles, three studies consist of 1915 cases and 1793 controls evaluated the association of CYP2E1 polymorphisms and breast cancer risk in rs2031920 C>T polymorphism (one in African, one in Asian and one in a mixed population) [14, 22, 23]; another four studies, with a total of 906 cases and 961 controls, was about CYP2E1*5 Rsa I/Pst I polymorphism (three in Asian and one in Arab) [15, 24, 25]; the rest four studies, including 1490 cases and 1653 controls, focus on CYP2E1*6 Dra I polymorphism (two in Caucasian, one in Arab and one in Asian) [25–27].