Studies have shown that COX-2–derived PGE2 promotes angiogenesis and tissue invasion of tumors, resistance to apoptosis, and suppression of immune responses in cancer (FitzGerald, 2011; Liu et al., 2015; Sheng et al., 2020); moreover, inhibition of COX-2 has been implicated in the treatment and prevention of various human cancers (Evans and Kargman, 2004). Here, PTGS2 is linked to cancer.