Aunt Zhang, 48, has recently been diagnosed with cervical cancer and colon cancer, and this series of unfortunate news has plunged her family into deep worry. It is confusing that she was suddenly faced with such a serious health problem, which was previously healthy. After careful medical history, the doctor found that Aunt Zhang's family history had obvious cases of cancer: her mother had died of colon cancer, and her two sisters had also had colon cancer, and other members of the family also had multiple cases of cancer. This condition caused particular concern among doctors, who suspected that Aunt Zhang's family might have Lynch syndrome. Further genetic testing confirmed this hypothesis: Aunt Zhang had the MSI-H gene, which is a common causative gene in patients with Lynch syndrome, indicating that it was a germline mutation inherited from her parents.
This finding is not only important for Aunt Zhang's treatment, but also reminds us that even if we live a healthy Xi and stay away from tobacco and alcohol, we may face the threat of cancer due to genetic factors. This underscores the importance of family history in medical diagnosis and serves as a reminder to stay vigilant about underlying genetic conditions.
There is indeed a genetic possibility for cancer
The occurrence of familial tumors involves multiple factors. On the one hand, the same family member may share an unhealthy lifestyle, and on the other hand, it may be caused by a mutation in an oncogene inherited in the family, often referred to as a "hereditary tumor". For this group of people, they have a significantly higher chance of developing certain tumors because they inherit genetic defects in their families. According to the American Cancer Society, about 5% to 10% of cancer cases are related to inherited genetic mutations. Although this percentage is not high, it is still not negligible. Professor Luo Rongcheng, Director of the Oncology Center of Southern Medical University and Chief Expert of the Department of Internal Medicine of Fuda Cancer Hospital Affiliated to Jinan University, emphasized that from the phenomenon of tumor family aggregation to molecular epidemiological studies of tumors, it is shown that tumors have a genetic predisposition. It is important to note that the inheritance pattern of the tumor is different from that of other genetic diseases, and it is not the type of disease that directly inherits the parents.
Inherited tumors can cause different types of tumors in family members, as mutations in one of the same disease genes can cause a variety of tumors, such as BRCA1 mutations, which can cause both breast and ovarian cancer. Therefore, awareness of the prevention of familial tumors is crucial. In 2016, the Journal of the American Medical Association published a major study conducted by scientists from Harvard University in collaboration with Danish and Finnish researchers, revealing that at least 22 types of tumors are genetic and may be passed down from family to family. Studies have shown that family members with a particular tumor have a 33% increased risk of other siblings with the same type of tumor. Different tumor types have different genetic risks. This study is believed to be the largest and longest study of the relationship between genetics and tumors to date. Elders with these cancers must be careful
Genetic factors in breast cancer
Studies have shown that some breast cancer patients carry a specific genetic marker, namely the BRCA1 or BRCA2 gene. These two genes play a key role in breast cancer susceptibility. For individuals carrying these genes, they may be up to 11 times more likely to develop breast cancer than the general population. This finding has important implications for early screening and prevention of breast cancer. Familial clustering of gastric cancer occurs in 5% to 10% of gastric cancer patients. In particular, in 1% to 3% of patients, we can observe the influence of genetic factors. Specifically, mutations in the CDH1 gene are associated with an extremely high risk (up to 80%) of diffuse gastric cancer. This underscores the importance of family history in the risk assessment of gastric cancer.
Environmental and genetic factors in lung cancer
Although lung cancer is not generally considered to be directly inherited, there is a clear tendency to cluster in families. This may be due to the fact that family members share similar living circumstances and dietary Xi, especially in families with smokers, where passive smoking increases the risk of lung cancer. In addition, certain inherited germline mutations (such as EGFR, ALK, RET, BRCA) and genes that activate ROS1 and RET cell enzymes in lung cancer are also associated with the development of lung cancer. About 10% of patients with pancreatic cancer who are genetically predisposed to pancreatic cancer show a family history of the disease. In particular, those with hereditary pancreatitis, familial malignant melanoma, or other inherited tumors have a significantly increased risk of pancreatic cancer. Therefore, individuals with these family medical histories need to be more concerned, but at the same time, they should not be overly concerned, because understanding the risks is for better prevention and early diagnosis.