The so far most commonly studied CYP2B6 SNP rs3745274 [30], which is a missense variant, where polymorphism is associated with for example lower hepatic expression and enzymatic activity for CYP2B6 [47], higher efavirenz exposure [48], plasma propofol concentrations [49] and increased breast cancer risk [50] was in low LD with the two top SNPs in this study (r2 = 0.29). This evidence concerns the gene CYP2B6 and breast cancer.