PTGS2 and lip and oral cavity carcinoma: The human COX-2 gene is located on chromosome 1 locus of 1q25.2–q25.3 and is 8.0 kbp in size with 10 exons [12]. COX-2 gene polymorphisms affect the expression levels and enzymatic activity of COX-2 and therefore are intimately linked to inflammatory response and individual variations in the susceptibility to oral cancers [13–15].