Relationship between ectopic expression of Wnt/β-catenin signaling pathway and Her2 overexpression in human breast carcinoma

Objective: To investigate ectopic expression of key elements of Wnt/β-catenin signaling pathway, including E-cadherin, β-catenin and Cyclin D1, as well as the relationship between ectopic expression of β-catenin and overexpression of Her2 in human breast carcinoma tissues. Methods: Immunohistochemical technique (Elivision) was used to detect the expression of Her2 and three elements of Wnt/β-catenin signaling pathway (β- catenin, E-cadherin, Cyclin D1) in 90 samples of human breast carcinoma. Results: In E-cadherin normally- expressed group, the ectopic expression rate of β-catenin (27.3%) was significantly lower than that (75.0%) in E-cadherin negative breast carcinoma; in β-catenin ectopic expression group, overexpression rate of Cyclin D1 (83.3%) was significantly higher than that (40.7%) in the other group. In Her2 overexpressed-breast carcinoma tissue, the ectopic expression rate of β-catenin (73.5%) was significantly higher than that (19.6%) in Her2 negative breast carcinoma. Her2 overexpression could coexist with ectopic expression of Wnt/β-catenin in promoting axillary lymph node metastasis in human breast carcinoma. Conclusion: Ectopic expression of Wnt/β-catenin signaling pathway does exist in some human breast carcinoma tissues, and the abnormal expression correlates with overexpression of Her2. Furthermore, the instantaneous activation of them could present synergism in promoting metastasis of axillary lymph nodes.