Expression And Significance Of β-catenin, CyclinD1 And P21^WAF1 In Thymic Tumors

Objective:To explore the expressions and significances ofβ-catenin,cyclinD1 and p21WAF1 in all types of thymic tumors.Methods:The 69 cases of thymic tumor was detected on the expressions of (3-catenin,cyclinDl and p21WAF1 by Immunohistochemical pv6000 method in 6 cases of type A,13 cases of AB,14 cases of type B1,13 cases of type B2,9 cases of B3 and 14 cases of type C (according to 2004 WHO Classification of thymic tumor).Results:The positive expression ratio of (3-catenin in thymic tomor was 53.26%, which was significantly higher than that of normal thymus(0%)(P=0.027).In types of A,AB,B1,B2,B3 and C of thymic tumors,the positive expression ratio ofβ-catenin were 33.33%,15.38%,28.57%,76.92%,77.78% and 85.71%,respectively. The positive expression ratio ofβ-catenin in thymic tomor were significantly different between groups(X2=24.676,P<0.01). The positive expressions ratio of P-catenin were significantly higher in the group of B2,B3 and C types than in that of A,AB,and B1 types(X 2=21.955,P<0.01). The positive expression ratio of cyclinDl in thymic tomor was 53.26%, which was significantly higher than that of normal thymus(0%)(P=0.027). In types of A,AB,B1,B2,B3 and C of thymic tumors,the positive expression ratio of cyclinDl were 33.33%,30.77%,35.71%,53.85%,77.78% and 85.71%,respectively. The positive expression ratio of cyclinD1 in thymic tomor were significantly different between groups(X2=14.393,P=0.013). The positive expression ratio of cyclinD1 was significantly higher in the group of B2,B3 and C types than in that of A,AB,and B1 types(X2=10.470,P<0.01). The positive expression ratio of p21WAF1 in thymic tomor was 39.13%, which was significantly lower than that of normal thymus. In types of A,AB,B1,B2,B3 and C of thymic tumors,the positive expression ratio of p21WAF1 were 66.67%,61.54%,57.14%,23.08%,22.22% and 14.29%,respectively. The positive expressions ratio of p21WAF1 in thymic tomor were significantly different between groups(X2=13.221, P=0.021). The positive expression ratio of cyclinD1 was significantly lower in B2,B3 and C types than in A,AB,and B1 types(X2=12.247, P<0.01).The positive expression ofβ-catenin in thymic tumors can be positively corelated with that of cyclinD1(r=0.449,P<0.01). The positive expression ofβ-catenin in thymic tumors can be negatively corelated with that of p21WAF1(r=-0.326,P=0.006).The positive expression of cyclinD1 in thymic tumors can be negatively corelated with that of p21WAF1(r=-0.445,P<0.01).Conclusion:1. The respective expression ofβ-catenin,cyclinD1 and p21WAF1 in each type of thymic tomors were significantly different. It suggests that they all could evaluate the malignancy of thymic tumors respectively, especially the differetiation of low-risk group (A,AB,and B1 types) from high-risk group (B2,B3 and C types).2. The expressions ofβ-catenin and cyclinDl present significantly positive correlation.β-catenin, as nuclear factor in Wnt pathway, may induce the overexpression of cyclinD1 in nucleus and further promote the occurrence and development of thymic tumors. Wnt pathway/β-catenin may take a role in the occurrence and development of thymic tumors. 3. p21WAF1, as a tumor suppressor, has significantly negative correlation withβ-catenin and CyclinDl on the expression. The possible machenism is that overexpression ofβ-catenin induces the activation P53-p21WAF1 pathway, resulting in the overexpression of CyclinDl and low or no overexpression of p21AF1. It suggests the diversity with the oncogenesis and development of thymic tumors. Therefore, combined detection ofβ-catenin,cyclinDl and p21WAF1 may has pivotal significance in the pathological category,malignancy and prognosis of thymic tumors.