The CYP2C19 deletion carrier frequency was only marginally higher in the breast cancer cases (31/842, 3.7%) when compared to the controls (17/497, 3.4%), being relatively high in both groups (sequence of the CYP2C19 deletion breakpoints and its surrounding area is presented in Additional file 2: Figure S1). Here, CYP2C19 is linked to breast carcinoma.