What is the average person's chance of getting cancer?

People are very concerned about whether malignant tumors are hereditary. Indeed, there are many reports about "cancer family" or "familial hereditary tumor". The most famous example is Napoleon's family of gastric cancer. Napoleon himself, his grandfather, his father, a brother and three sisters all suffered from gastric cancer and all died of it. Animal experiments have confirmed that some cancers are related to heredity. After mating with mice with the same tumor, their offspring will also have the same tumor, and the incidence of cancer will increase from generation to generation after several generations. But the so-called tumor inheritance is actually not the inheritance of the tumor itself, but only a tendency or susceptibility to the tumor. On this basis, combined with the role of carcinogenic factors in the environment, after a complex canceration process, tumors can be produced.

Genetic investigation on the family history of tumor or twins found that some cancers have family accumulation in human cancers. The high proportion of twins suffering from cancer at the same time also shows that some cancers are related to heredity. According to the cancer survey of foreign population, after Guangdong people moved to Shanghai or Beishangguang, the incidence of nasopharyngeal carcinoma in their offspring was still higher than that of local people. The incidence of gastric cancer in Japan is very high, and the incidence of Japanese expatriates who immigrated to the United States is higher than that of locals. The border areas of Henan, Hebei and Shanxi provinces in China are high incidence areas of esophageal cancer, and 65% patients with esophageal cancer have family history. It is also found that two generations in the family have esophageal cancer at the same time. Similarly, in the investigation of the high incidence area of liver cancer in Qidong County, Jiangsu Province, it was found that both father and son had many cases of liver cancer.

Tumors with obvious genetic tendency include retinoblastoma, colonic polyp syndrome, nephroblastoma and neuroblastoma. These tumors are easily passed on to children, just as their genetic characteristics (such as hair and eye color) are passed on to children. These tumors belong to dominant inheritance, and a child of a hereditary tumor patient will have a half chance of inheriting oncogenes and developing cancer. These hereditary tumors usually occur in adolescence, and the tumors are often multiple.

Tumors with familial susceptibility include breast cancer, colon cancer, malignant melanoma and lung cancer. If a person's immediate family members (such as parents, brothers and sisters) suffer from one of the above cancers, then his chance of suffering from this tumor is 2-3 times higher than that of the general population.

Understanding the genetic law of the above-mentioned tumors and mastering the family history of tumors is helpful to guard against and attach importance to the occurrence of familial tumors, to early detection, early diagnosis and early treatment, and to the study of cancer etiology and prevention.