ABSTRACT
Objective To investigate the expression and significance of epithelial cell adhesion molecule (Ep-CAM) in breast cancer.Methods Twenty-three cases of breast cancer tissue samples and paired lymph node metastases confirmed pathologically were collected.Isobaric tags for relative and absolute quantitation (iTRAQ) proteomics technology was used to screen and identify the differentially expressed proteins between primary tumor and lymph node metastasis of breast cancer.The expression of Ep-CAM was detected by Western blotting in 4 cases of primary breast cancer tissues and paired lymph node metastases.And the expressions of Ep-CAM in 252 cases of breast lesions were detected by immunohistochemical method.Results Quantitative proteomic examination results showed that differentially expressed proteins existed in breast cancer primary tumor and lymph node metastasis,and the expression of Ep-CAM in metastatic lesions was higher than that in primary tumor.Western blotting results showed that the expression of Ep-CAM in metastatic lesions (1.46 ± 0.22) was higher than that in primary tumor (1.16 ± 0.09),which was consistent with the results of proteomic.The immunohistochemical results showed that the positive expression rate of Ep-CAM in lymph node metastasis tissues (93.16％,109/117) was significantly higher than that in primary breast cancer without metastasis (72.73％,64/88),and the difference was statistically significant (x2 =15.921,P =0.000).The positive expression rate of Ep-CAM in primary breast cancer with lymphatic metastasis (72.65％,85/117) was lower than that in paired lymph node metastases (P =0.001).Conclusion Ep-CAM is differentially expressed in primary tumor and lymph node metastasis of breast cancer,which may be related to the lymphatic metastasis of breast cancer.