Association of maspin expression with the malignancy grade and tumor vascularization in breast cancer tissues.

Maspin belongs to a tumor suppressing protein which is usually expressed highly in myoepithelial cells, and is significantly downregulated in breast cancer cells. We focused on identifying the correlation between maspin expression and the clinicopathological features of human breast cancer tissues using immunohistochemistry. There was a significant correlation in that maspin-positive tumor specimens showed a low pathological grade of malignancy, such as a lower infiltration of the tumor into the surrounding tissue and a downregulation of c-erbB2 expression. Moreover, maspin-positive cases showed a significant decrease in tumor vessels positively stained with anti-factor VIII-related antigen antibody. These results suggest that maspin production in myoepithelial cells could downregulate the malignant phenotype of breast cancer.