No significant associations were observed between SII groups (low SII group vs. high SII group) and the following parameters: gender, BMI, maximum tumor diameter, lymphovascular invasion, presence of psammoma bodies, Ki67 index, gene mutation status TILs, prevalence of concurrent Hashimoto’s thyroiditis, LNM, capsular invasion, multifocal tumor, and bilateral thyroid tumor (all P > 0.05). The gene discussed is MKI67; the disease is Hashimoto thyroiditis.