Abstract: Abstract］  Objective To study expression and significance of Wnt inhibitory factor1(WIF1), βcatenin and chclin D1 in Wnt/βcatenin signal transduction pathway in papillary thyroid cancer（PTC）. Methods Sixty cases of PTC were selected and the specimens of cancerous foci and adjacent tissues were taken. The expression of WIF1, βcatenin and cyclin D1 mRNA and protein were detected, and the correlation between WIF1 mRNA and βcatenin, cyclin D1 mRNA was analyzed. ResultsThe expression levels of WIF1 mRNA and positive rates of WIF1 protein expression in PTC tissues were significantly lower than those in paracancerous tissues(P＜005), while expression levels of βcatenin, cyclin D1 mRNA and protein in PTC tissues were on the contrary(P＜005). And the expression levels of WIF1 mRNA and protein in PTC lymph node metastasis group was lower than those without lymph node metastasis, but the expression levels of βcatenin, cyclin D1 mRNA and protein in PTC lymph node metastasis group were on the contrary(P＜005). There were no statistically significant differences in the expression levels of WIF1, βcatenin, cyclin D1 mRNA and positive rates of protein in PTC tissues in different sex, age, tumor diameter, number of lesions and whether or not the capsule was invaded(P＞005). Expression levels of βcatenin, cyclin D1 mRNA were negatively correlated with those of WIF1 mRNA(P＜005). ConclusionThe down regulation mechanism of WIF1 gene in PTC tissues promoted the accumulation of βcatenin protein in the cytoplasm, which resulted in over activation of target gene cyclin D1. The WIF1 down regulation or βcatenin and cyclin D1 up regulation mechanism may play an auxoaction role in the occurrence and metastasis in PTC.

Key words: thyroid neoplasms, Wnt signaling pathway, beta catenin