In the past, the incidence of thyroid cancer was low in China, with an average annual incidence of 1.49/100,000 people, 0.9/100,000 men and 2.0/100,000 women, accounting for 0.86% of all tumors and the first place of all head and neck tumors. In recent years, the incidence has been on the rise. The age of onset increases significantly after 20 years old, reaches a peak at 30-34 years old, and decreases significantly after 54 years old. Common pathogenic factors: 1. Oncogenes: A variety of nucleogenic oncogenes, expressed in thyroid follicular cells, play an important role in cell growth and differentiation. Overexpression of normal genes, altered gene expression, as well as loss of inhibitory genes and oncogene amplification can all contribute to cellular malignancy and malignancy. 2.Growth factors: such as thyroid stimulating hormone, insulin-like growth factor, transforming growth factor, etc. The ptc oncogene was isolated from papillary thyroid cancer cells. 3.Ionizing radiation: X-rays are more carcinogenic than iodine 131. The mechanism of carcinogenesis is that radiation induces cell mutation to promote growth, and can kill some cells at sublethal amount to reduce TH secretion, and feedback to pituitary thyroid cells to increase TSH production and promote proliferation and carcinogenesis of potentially malignant cells. It is widely accepted that radiation is a causative factor for thyroid cancer. Local irradiation with radioisotopes, internal irradiation, and treatment of adult hyperthyroidism with iodine 131 have not been found to be correlated with the occurrence of thyroid cancer. 4. Iodine deficiency: the relationship with the occurrence of thyroid tumors is still unclear. Not only is thyroid cancer more frequent in endemic goiter areas, but it also occurs more frequently in coastal areas with high iodine levels. Most of the goiters are filter cell carcinoma and some of them are interstitial carcinoma, while most of them are papillary carcinoma in high iodine areas. 5.Family factor: It has a certain genetic tendency, with 3.5-6.2% possibility of having thyroid cancer together. 6.Female hormone: The growth of thyroid gland is governed by TSH, which plays a role in promoting thyroid cancer. There are high levels of female hormone receptors in papillary thyroid cancer tissues, and female hormones may be one of the cancer-causing factors. 7.Other: Thyroid hyperplasia, such as adenomatous goiter and hyperfunctioning goiter, has a combination of thyroid cancer in about 5% and 2% respectively. A small number of thyroid adenomas can become cancerous after years of growth.