The objective of the present study was to investigate and analyze the epithelial-cadherin (E-cadherin) expression in invasive ductal carcinoma of the breast, and to analyze the associations between the expression and clinicopathological characteristics of lymph node metastasis and the prognosis of breast cancer. The immunohistochemical streptavidin-peroxidase method was used to detect the E-cadherin expression in 30 cases of breast fibroadenoma and in 450 cases of invasive breast cancer, and then the χ2test and Kaplan-Meier method were used to analyze the data. The 30 cases of breast fibroadenoma showed positive expression of E-cadherin. Specifically, results found that E-cadherin was highly expressed in 49.04% (77/157) of patients with non-metastatic breast cancer, while low expression was found in 50.96% (80/157). Additionally, E-cadherin was highly expressed in 29.69% (87/293) of patients with lymph node metastasis of breast cancer, with low expression in 70.31% (206/293); these differences were significantly different (χ2=16.53; P<0.001). E-cadherin was expressed in 35.48% (22/62), 33.73% (84/249), 63.83% (30/47) and 30.43% (28/92) of patients with luminal A type, luminal B type, human epidermal growth factor receptor-2positive and triple-negative breast cancer (TNBC), respectively. It was found that patients with high expression of E-cadherin had a better prognosis than the low expression group with regards to TNBC, and this result was significantly different (χ2=4.48; P=0.034). In conclusion, low E-cadherin expression was associated with lymph node metastasis in invasive breast cancer, and the patients with low expression also had a poor prognosis compared with those in the high expression group. The present results suggested that E-cadherin could be used in a prognostic index for patients with lymph node metastasis and TNBC.
Keywords: breast cancer; epithelial-cadherin; lymph node metastasis; molecular typing.