Diffuse growth pattern affects E-cadherin expression in invasive breast cancer.

We investigated the correlations between growth patterns and E-cadherin expression by immunohistochemistry and the presence of mutations of exons 6-10 of the E-cadherin gene by PCR-SSCP, in 79 cases of invasive lobular and ductal breast cancer. E-cadherin expression showed a tendency to be lower in lobular than in ductal carcinomas (p=0.064). In 60% of lobular carcinomas the diffuse growth pattern and in 72% of ductal carcinomas the compact growth pattern predominated. E-cadherin expression was significantly lower in diffuse than in compact tumor area (p<0.001) and not related to carcinoma type when it was considered in tumor areas with either diffuse (p=0.278) or compact (p=0.128) growth pattern. No mutations were detected. In conclusion, loss of E-cadherin expression is related to an increase of diffuse growth pattern in both lobular and ductal types of breast cancer, and the differential proportions of growth patterns in both tumor types cause the tendency for lower E-cadherin expression in the lobular type.