GSTP1 and esophageal squamous cell carcinoma: Here, we analyzed the association of various habits related factors (like tobacco chewing, beedi and cigarette smoking, BQ chewing and alcohol consumption) and carcinogen metabolizing gene polymorphisms (GSTM1, GSTT1) in ESCC and also stratified by promoter hypermethylation of TSGs, like p16, DAPK, BRCA1 and GSTP1 by logistic regression analysis.