Ring finger protein 43 (RNF43) is a ring-type E3 ubiquitin ligase.As a negative regulater of Wnt signaling pathway, RNF43 has an important anti-tumor effect.The mutation of RNF43 may cause abnormal activation of Wnt signaling pathway, and then promote invasion, metastasis and proliferation of tumor cell.In addition, the act of RNF43 protein in the Wnt signal pathway is expected to be a molecular target in the therapy of cancer.In recent years, with the gradual deepening of related research, the molecular structure of RNF43 protein and its mechanism of action with the Wnt pathway-related proteins have been gradually clear.In clinical, RNF43 protein analogs and related vaccine also show the important position in the therapy of cancer.

Objective To detect the expression and function of ZNRF3 in different kinds of thyroid cancer tissues and cells.Methods Immunohistochemistry was used to detect the expressions of ZNRF3 protein in 35 cases of papillary thyroid carcinoma and 10 cases of poorly differentiated thyroid carcinoma.The expressions of ZNRF3 gene in TPC-1 and 8505C were detected by RT-PCR,and the cell lines were derived from papillary thyroid carcinoma and poorly differentiated thyroid carcinoma respectively.After silenced ZNRF3 gene expression with lentivirus,the proliferation ability of TPC-1 cells were detected with CCK-8,the invasion and metastasis ability of TPC-1 cells were detected with Transwell.Results According to results of immunohistochemistry and RT-PCR,the expressions of ZNRF3 in papillary thyroid carcinoma cells and tissues were higher than those in poorly differentiated thyroid carcinoma cells and tissues,the differences were statistically significant (4.83±0.44 vs.3.13 ±0.59,t =2.20,P ＜0.05;1.01±0.06 vs.0.21±0.04,t =11.80,P＜0.01).After ZNRF3 geng silencing,according to the results of CCK8,the proliferation ability of TPC-1 cells was significantly enhanced in 72 h,the difference was statistically significant (0.96 ± 0.10 vs.0.64 ± 0.05,t =3.19,P ＜ 0.05);and according to the results of Transwell,the TPC-1 cell's invasion (0.12 ± 0.01 vs.0.09 ±0.00,t =5.48,P＜0.01) and migration (0.22 ±-0.01 vs.0.17 ±0.01,t =4.58,P ＜0.05) also increased,the differences were statistically significant.Conclusion The expression of ZNRF3 in papillary thyroid carcinoma is higher than that in poorly differentiated thyroid cancer.ZNRF3 is tumor suppressor gene in the thyroid tumors.