In particular, in the case of oral cancer, in vitro studies showed that curcumin can hinder cancer cell growth by inhibiting the progression of the S/G2M phase [65,66], enhance the cytochrome P450 expression, so reducing the risk of developing cancer [67], promote apoptosis of oral cancer cells by inhibiting cyclooxygenase-2 (COX-2), and increase the RT sensitivity [68,69]. The gene discussed is PTGS2; the disease is cancer.