GSTM1 and lip and oral cavity carcinoma: Since oral cancer is a global health concern and alcohol and tobacco consumption are major risk factors involved in its carcinogenesis, the aim of this study was to evaluate the Fagerström and AUDIT tests as likely screening tools for oral cancer and their correlation with the expression of CYP1A1, GSTM1, GSTP1, and GSTT1 genes measured by the RT-qPCR method.