As mentioned above, on the whole, loss of MUC4/Y’s unique domains weakened the roles of MUC4/Y on malignant activities, and impaired expression levels of downstream effector molecules of MUC4/Y triggering, demonstrating that MUC4/Y’s unique domains have significant roles in MUC4/Y-mediated malignant function of pancreatic cancer, downstream of molecule mechanisms, including signaling pathways, respectively. The gene discussed is MUC4; the disease is familial pancreatic carcinoma.