Tumor and normal tissues have no significant difference in COX-1 expression, but COX-2 has significantly higher expression in tumor tissues, including digestive cancers such as colon, gastric, esophageal, and pancreatic cancer, and in lung, breast, bladder, cervical, and head and neck cancer and brain tumors [73]. The gene discussed is PTGS2; the disease is familial pancreatic carcinoma.