Expression of the human MTA1 gene in breast cell lines and in breast cancer tissues.

MTA1 was reported as a metastasis-associated gene. Tumors with higher MTA1 mRNA level were shown to have higher rates of invasion and lymph node metastasis and tended to have higher rates of vascular involvement. The majority of invasive breast carcinomas were demonstrated to overexpress MTA1 compared to surrounding normal tissues. MTA1 was also found to be more expressed in metastatic breast cancer cell lines than in nonmetastatic ones. Originally we were interested in analyzing factors differently expressed in invasive and noninvasive breast cancer cell lines. Therefore we analyzed expression of MTA1 together with several other genes in correlation with cell invasiveness in 25 breast epithelial cell lines. Furthermore, we analyzed it in 90 primary breast tumor tissues and examined its correlation with expression of estrogen receptor, progesterone receptor, plasminogen activator inhibitor-1, E-cadherin, histopathological data, disease-free survival, and overall survival. Our results demonstrated that MTA1 expression was significantly higher in noninvasive cell lines than in invasive ones. It also correlated positively with expression of noninvasive factors and reverse correlated with invasive factors in both cell lines and tumor tissues.