PTGS2 and cancer: Overexpression of COX-2 has been detected in various types of cancer with a number of studies reporting that COX-2 expression levels were significantly higher in OSCCs compared to normal tissue (Byatnal et al., 2015; Goulart Filho et al., 2009; Lee, Kang & Kim, 2015; Moazeni-Roodi et al., 2017; Tang et al., 2003) and overexpression of COX-2 correlated with poor prognosis in cervical SCCs following radiation (Gaffney et al., 2001).