ABCB1 and colorectal carcinoma: We are convinced that after further validation (also on larger numbers of cases and controls) the combination effects of low blood-As levels with CAT rs1001179-nonCC, ABCB1 rs2032582–CC, GPX1 rs1050450-CC, CRTC3 rs12915189-nonGG maybe a suitable CRC biomarker in Polish women.