MMP13 is potentially a new tumor marker for breast cancer diagnosis.

Within the past decade, the incidence of breast cancer in Taiwan has been rising year after year. Breast cancer is the first most prevalent cancer and the fourth leading cause of cancer-related deaths among women in Taiwan. The early stage of breast cancer not only have a wider range of therapeutic options, but also obtain a higher success rate of therapy than those with advanced breast cancer. A test for tumor markers is the most convenient method to screen for breast cancer. However, the tumor markers currently available for breast cancer detection include carcinoembryonic antigen (CEA), carbohydrate antigen 15.3 (CA15.3), and carbohydrate antigen 27.29 (CA27.29) exhibited certain limitations. Poor sensitivity and specificity greatly limits the diagnostic accuracy of these markers. This study aims to identify potential tumor markers for breast cancer. At first, we analyzed genes expression in infiltrating lobular carcinoma, metaplastic carcinoma, and infiltrating ductal carcinoma of paired specimens (tumor and normal tissue) from breast cancer patients using microarray technology. We selected 371 overexpressed genes in all of the three cell type. In advanced breast cancer tissue, we detected four genes MMP13, CAMP, COL10A1 and FLJ25416 from 25 overexpressed genes which encoded secretion protein more specifically for breast cancer than other genes. After validation with 15 pairs of breast cancer tissue and paired to normal adjacent tissues by membrane array and quantitative RT-PCR, we found MMP13 was 100% overexpressed and confirmed to be a secreted protein by Western blot analysis of the cell culture medium. The expression level of MMP13 was also measured by immunohistochemical staining. We suggest that MMP13 is a highly overexpressed secretion protein in breast cancer tissue. It has potential to be a new tumor marker for breast cancer diagnosis.