Cancer (malignant tumor) is not contagious and will not be transmitted. However, there are individual tumors because their occurrence is related to infectious diseases, for example, liver cancer is usually cancerous on the basis of chronic hepatitis B. Therefore, although liver cancer is not contagious, liver cancer patients usually have hepatitis B, which is a contagious disease, so they should pay attention to it. Can cancer be hereditary? This question is relatively complicated. Although a few tumors are hereditary, such as Von Hippel-Lindau (VHL) disease, which is an autosomal dominant familial neoplastic disease. The main manifestations are central nervous system hemangioblastoma, retinal hemangioma, renal cell carcinoma, adrenal pheochromocytoma, and cysts or tumors of the pancreas, kidney, epididymis, and other organs. Most cancers are not directly inherited (dominant or recessive) like common genetic diseases, but are closely related to genetic factors. This relationship with genetic factors is manifested in the inheritance of susceptibility to tumors, so that members in families with a high incidence of tumors may have a higher likelihood of developing tumors.