Thyroid cancer (TC), the most common malignancy of the endocrine system, is currently the fifth most common malignancy diagnosed in women (1). The incidence of TC in the United States has increased by an average of 3% per year over the past 4 decades. Much progress has been made in exploring the etiology and pathogenesis of thyroid cancer, while the exact etiology remains unknown, TC is thought to arise from interactions between genetic susceptibility factors, epigenetic effects, and various environmental factors. Besides the improvement of diagnosis, TC increasing incidence emphasize that other important factors such as the environment play an important role in disease pathogenesis. While microbiota as an environment factor to some cancers accept widespread attention, if microbiota also as a risk factor for TC, it is worthy to be considered.

Thyroid cancer (TC), the most common malignancy of the endocrine system, is currently the fifth most common malignancy diagnosed in women (1). The incidence of TC in the United States has increased by an average of 3% per year over the past 4 decades. According to the China National Cancer Registry data in 2015 (3), there were estimated 90,000 new TC cases in China, and its incidence has risen sharply. Much progress has been made in exploring the etiology and pathogenesis of thyroid cancer, while the exact etiology remains unknown, TC is thought to arise from interactions between genetic susceptibility factors, epigenetic effects, and various environmental factors. Besides the improvement of diagnosis, TC increasing incidence emphasize that other important factors such as the environment play an important role in disease pathogenesis. While microbiota as an environment factor to some cancers accept widespread attention, if microbiota also as a risk factor for TC, it is worthy to be considered.

Inclusion Criteria:

• Aged 18 to 65 years
• Patients of thyroid cancer

Exclusion Criteria:

• Pregnancy
• Lactation
• Cigarette smoking
• Alcohol addiction
• Hypertension
• Diabetes mellitus
• Lipid dysregulation
• BMI > 27
• Recent (< 3 months prior) use of antibiotics, probiotics, prebiotics, symbiotics, hormonal medication, laxatives, proton pump inhibitors, insulin sensitizers or Chinese herbal medicine
• History of disease with an autoimmune component, such as MS, rheumatoid arthritis, IBS, or IBD
• History of malignancy or any gastrointestinal tract surgery

All patients were included according to the inclusion and exclusion criteria