Abstract: Objective To investigate the relationship between the expression of carcinoembryonic antigen related cell adhesion molecule 6 (CEACAM6), miR-146b and calcium-binding protein A6 (S100A6) and clinicopathological features and prognosis in thyroid cancer. 
Methods A total of 165 thyroid cancer patients who underwent thyroidectomy in our hospital were selected. The expressions of CEACAM6, miR-146b and S100A6 were detected by real-time fluorescence quantitative polymerase chain reaction (RT-PCR) in cancer tissues and adjacent tissues, respectively. A t-test was used to examine the expression differences of CEACAM6, miR-146b and S100A6 among different clinicopathological features of thyroid cancer patients. Kaplan-Meier and Cox proportional risk models were used to analyze the relationship between CEACAM6, miR-146b, S100A6 expression and prognosis of thyroid cancer patients. 
Results The expressions of CEACAM6, miR-146b and S100A6 in cancer tissues were higher than those in adjacent tissues (P＜0.05). The expressions of CEACAM6, miR-146b and S100A6 in patients with tumor diameter ＞1 cm, low differentiation, T3- T4b and N1a-N1b were higher than those in patients with tumor diameter ≤1 cm, high differentiation, T1- T2 and N0 (P＜0.05). The overall survival rate of patients with high expression of CEACAM6, miR-146b and S100A6 were lower than those with low expression of CEACAM6, miR-146b and S100A6 (P＜0.05). High expression of N1a-N1b, CEACAM6, miR-146b and S100A6 were risk factors for poor prognosis of thyroid cancer patients (P＜0.05). 
Conclusion CEACAM6, miR-146b and S100A6 are highly expressed in thyroid cancer tissues, which are related to the clinicopathological features and poor prognosis of thyroid cancer. 

Key words: thyroid neoplasms, carcinoembryonic antigen, calcium-binding protein A6