Can cancer be hereditary or not? This is the question of many people, doubts and panic! Especially the family members who have tumor patients in their family or close relatives. In the era of cancer talk, early prevention and early detection and treatment are the key, let’s share it together! Early diagnosis and treatment of tumor is very necessary because it is the only one method so far that can really reduce the incidence and mortality of tumor. 1. Am I a high-risk group for cancer? What is the most important first step of early diagnosis and treatment of cancer? The most important first step is to identify the high-risk group. Not everyone and not every age group needs to have early diagnosis and treatment of cancer! Only those who are at high risk for specific cancers need special attention for early detection, treatment and intervention with appropriate methods. One of the most important ways to identify people at high risk of cancer is genetic testing. First, genes with high epigenetic prevalence are extremely risky individuals, which are not influenced by the environment and have a high cancer rate. The other part is the inheritance to the parental generation such as inherited from the parents, which is more likely to cause corresponding changes under environmental factors. These two types of carriers with genetic background we call as high risk group. 2.What are the chances that I will get cancer if my relative has cancer? Cancer can be inherited, but just because someone in the immediate family has cancer, it does not mean that the whole family is a high-risk group. Only those cancer genes are confirmed to be inherited to the next generation, and then the genes of the next generation will have the susceptibility. But susceptibility alone is often not enough. Approximately 70% or more of cancer cases are caused by the interaction of genes and the environment. In terms of the etiology of cancer, there is a distinction between high and low prevalence genes. The essential difference lies in the ratio of genetic and environmental influences. Genes with high prevalence are passed on to the next generation and have a very high tumor prevalence and are largely independent of environmental factors, such as retinoblastoma. For hereditary cancers with lower ectopic rates, environmental factors play a large role and are often influenced by a variety of environmental factors such as smoking and UV exposure. The tumor that arises from the interaction of environmental and genetic influences is a more variable tumor and has a greater likelihood of developing the disease compared to people without a genetic background. Therefore, people with a family history of cancer should not be overly nervous. On the one hand, they should realize that they have a possible increased risk of cancer due to a family history of cancer, consult with experts in tumor genetics to determine whether it is hereditary cancer, and if there is a clearly known cancer-related gene mutation, it should be prevented and treated as early as possible. For example, a family with more than one immediate family member suffering from colorectal cancer or breast cancer must pay high attention to the possibility of inheriting these two types of cancer. It is best for immediate family members to have early genetic screening and regular checkups for confirmed carriers. 3. The most common cancer that can be easily inherited – Lynch syndrome Lynch syndrome is also called hereditary non-polyposis colorectal cancer. It is a genetic susceptibility to colorectal cancer and certain other cancers (such as endometrial cancer and gastric cancer) caused by mutations in the mismatch repair (MMR) gene. More intensive colonoscopy should be given earlier to relatives diagnosed with Lynch syndrome (positive for the MMR gene mutation), and further surveillance for endometrial cancer risk may be considered for female preexisting patients or relatives who develop Lynch syndrome. For carriers of genetic mutations without colon cancer, colonoscopy should be performed from the age of 20 to 25 years (or 10 years before the age of diagnosis of the earliest diagnosed colon cancer in the family), once every 1 to 2 years, and once a year after the age of 35 years, and removal of colon adenomas found during the examination can effectively prevent colorectal cancer. The peak periods of colon cancer are 20-29 years old and 40-49 years old, so it is recommended that people with such family history of the disease had better do preventive examinations early, etc.