Sachse et al. [8] conducted a multicenter case-only study on 490 CRC patients and 593 controls, finding no significant interactions between GST and CYP1A1. However, in a recent case-control study in China, we have demonstrated that the combinations of GSTT1 and GSTM1 as well as CYP1A1*2A and GSTT1 are significantly associated with CRC [29]. The gene discussed is GSTM1; the disease is colorectal carcinoma.