Thyroid cancer is the most common tumor of the endocrine system and according to the American Cancer Society, it is the fifth most common malignancy in women and the fourth most common malignancy in Asian women. There are four pathological types of thyroid cancer: papillary, follicular, medullary and undifferentiated carcinomas. Thyroid cancer has a high degree of familial aggregation, and this familial aggregation can be broadly classified into three types: familial medullary carcinoma, familial papillary carcinoma, and thyroid cancer occurring in patients with tumor syndrome. Medullary carcinoma is a more common hereditary cancer in Europe and the United States, and about 20% of medullary carcinomas in Europe and the United States are hereditary, while the data for Chinese people are less. Inherited medullary carcinoma can manifest as familial medullary carcinoma, type II multiple endocrine neoplasia syndrome (MEN2), which originates from parafollicular cells of the thyroid gland, and most medullary carcinomas secrete calcitonin, which is the main diagnostic marker for medullary carcinoma. hyperparathyroidism, MEN2B patients include medullary thyroid carcinoma, pheochromocytoma and some other disease conditions of the mucosal and skeletal systems, and patients with familial medullary carcinoma resemble MEN2A but lack other non-medullary carcinoma conditions. Germline mutations in the RET gene (10q11.2) are a common cause, and are inherited in an autosomal dominant fashion, but with varying rates of episiotropy. 2009 American Thyroid Federation guidelines recommend that all patients with medullary carcinoma be analyzed for mutations in the RET gene, and that family members at risk receive prophylactic thyroidectomy once mutations in the RET gene are identified. The guidelines recommend that all patients with medullary carcinoma be analyzed for RET mutations. Extensive data show that patients who undergo prophylactic thyroidectomy for mutant RET carriers have better outcomes than those who are operated on after symptoms are detected. Although medullary carcinoma is a highly heritable tumor, it accounts for a total of 2-4% of thyroid cancers, with papillary carcinoma being the most common type of thyroid cancer (approximately 90%). A recently published cohort study from Northern Europe of 63,495 first-degree relatives of 11,206 non-medullary thyroid cancers diagnosed between 1955 and 2009 showed that the prevalence of first-degree relatives of women with thyroid cancer was three times higher than the normal population and that twins were 23 times more likely to develop thyroid cancer, suggesting that non-medullary thyroid cancers also have a high familial This suggests that non-medullary thyroid cancer also has a high familial clustering. The author has screened his own patients for papillary thyroid cancer and found that 9.3% of them had a family history of papillary cancer. Unlike medullary carcinoma, there is no definitive genetic test to diagnose familial papillary carcinoma. Genome-wide association analysis has identified several specific polymorphic loci that are associated with susceptibility to papillary carcinoma. The author’s study in Chinese identified chromosome 14q13.3 (P=8.0×10-11), 9q22.33 (P=1.0×10-4), 2q35 (P=1.7×10-3), and 8p12 (P=1.1×10-4) regions as PTC susceptibility regions, and combining the risk alleles in these regions could predict the susceptibility of papillary carcinoma to some extent. In addition to the aforementioned MEN2 syndrome, Cowden syndrome (PTEN gene, RASAL1 gene), DICER1-related disease (DICER1 gene), hereditary paraganglioma syndrome (SDHx gene), and familial adenomatous polyposis (APC gene) all have a certain percentage of thyroid cancer, and once these syndromes are diagnosed The thyroid gland needs to be evaluated and followed up once these syndromes are diagnosed. Although thyroid cancer has a high familial aggregation and mutation testing for the RET gene has been included as a guideline and mandatory program in the management of medullary carcinoma abroad, the familial nature of thyroid cancer has not yet received sufficient attention in China. An important reason is that physicians are not sufficiently aware of familial thyroid cancer, which, combined with busy medical workloads, makes the collection and recording of family and past histories incomplete, resulting in the lack of scientific, large-sample data from current studies based on medical history records to show how many Chinese have hereditary medullary thyroid cancer and what percentage of thyroid cancers are in patients with tumor syndromes, not to mention The probability and type of mutation of the above mentioned mutated genes in the Chinese population. Therefore, if we want to improve the management and treatment of familial thyroid cancer, the most feasible and rapid way is to standardize the method of taking family history and past history, improve the level of history taking without significantly increasing the workload of doctors, and establish a comprehensive analysis model based on the disease registration system, as well as networking with the information of family members, in order to obtain accurate patterns and frequencies of familial diseases. frequency. Of course, this is a systemic project, and even with the establishment of this registry, it is still affected by the outlier rate and age of onset of the disease, making it impossible to diagnose and advise some early stage patients. For example, mutation analysis of the RET gene is recommended in the United States for all patients with medullary carcinoma, and in the case of mutation-positive patients, mutation analysis can be performed in their family members regardless of the presence or absence of thyroid nodules, making it possible to identify high-risk individuals early in the absence of disease. All applications of mutation analysis results for family history, past history, and susceptibility genes should insist on informed consent, while taking care to protect the patient’s right to privacy. Since thyroid cancer is more prevalent in females, with earlier age of onset and higher age of childbirth, the social pressure on thyroid cancer patients of childbearing age is now enormous. How to raise the population’s attention to the family aggregation of thyroid cancer without causing social panic may require more communication, education, understanding and even tolerance to solve this social problem. If the testing of susceptibility genes such as RET and PTEN is routinely carried out, the interpretation of test results, the protection of patients’ privacy, and the impact on commercial factors such as health insurance will require comprehensive discussions on ethics and legislation to be more regulated. With the improvement of next-generation sequencing technology and the reduction of cost, the whole genome sequencing can be performed for about 20,000 RMB at present, and the arrival of the era of individualized medicine caused by this will not be far away anymore, but the social and medical problems brought by this also deserve attention.