Two meta-analyses22,25 illustrated that the CYP1A1 MspI polymorphism may be associated with oral cancer susceptibility in Asians as well as Xie et al.81 in a stratified analysis by ethnicity, showed significant evidence of the association of CYP1A1 MspI polymorphism with the HNC risk in Asian ethnicity, but not mixed and Caucasian ethnicities. This evidence concerns the gene CYP1A1 and lip and oral cavity carcinoma.