The effect of iodine on papillary thyroid cancer has been controversial for many years. The investigators designed a cross-sectional study and aimed to explore the relationship between the serum and urine iodine levels and the clinical and molecular characteristics of papillary thyroid cancer.

Inclusion Criteria:

• Age range: 18~65 years old, gender not limited;
• Living in the residential area for at least 5 years;
• Patients diagnosed clinically with thyroid cancer and scheduled for thyroid surgery, with pathological diagnosis of papillary thyroid cancer;
• Complete clinical data: including general information, relevant laboratory tests, pathological reports, surgical reports, ultrasound reports, etc.

Exclusion Criteria:

• Pathological diagnosis of other types of thyroid cancer;
• Diagnosed with other types of cancer;
• There are serious comorbidities of the heart, liver, and kidneys;

Three sub centers will be selected in high iodine areas (Jining, Liaocheng, Heze) and moderate iodine areas (Jinan, Shenyang, Harbin) respectively. People who have lived in these areas for more than 5 years and seek medical treatment in tertiary hospitals will be selected.