Differential expression of E-cadherin in lobular and ductal carcinoma of breast: Diagnostic implications

Background: E-cadherin is a transmembrane glycoprotein that binds similar types of cells together. Many researchers have noted that E-cadherin is present in numerous cases of ductal carcinoma, and absent in most cases of lobular carcinoma. Therefore, this marker can be used to distinguish these tumors, which is clinically important. Methods: We studied 80 cases of breast carcinoma. On the basis of morphologic features (classic/indeterminate) we divided them into unanimous (42 cases) and non-unanimous (38 cases) groups. Immunohistochemistry (IHC) studies carried out on all cases were scoredfrom zero to 300, by multiplying the intensity of staining by the percentage of cells exhibiting positive staining. Results: Different expression of E-cadherin in the unanimous group was statistically significant (p=0.0009). On the basis of analytical statistic, score of 7.5 was discriminative between ductal and lobular carcinoma with high sensitivity. We used this score for final diagnosis of non unanimous group, in which 22 cases of ductal carcinoma and 16 cases of lobular carcinoma were diagnosed. Out of the 80 cases studied, in 13 cases primary diagnosis of lobular carcinoma was changed into ductal carcinoma and in three cases the result was vice versa. There is no correlation between expression of E-cadherin with tumor size, tumor grade (in ductal type) and lymph node metastasis. Conclusion: E-cadherin expression is a useful diagnostic tool in distinguishing of ductal from lobular carcinoma of breast.