Down regulation of the tumor suppressor gene maspin in breast carcinoma isassociated with a higher risk of distant metastasis

Background: Maspin (mammary serpin) is a relatively novel serine protease i nhibitor with tumor suppressing function in breast cancer. Maspin expressio n was found in normal breast epithelial cells, but was decreased during tum or progression. Only a few systematic analyses of this phenomenon have been undertaken so far. In this study we developed specific nested reverse tran scription polymerase chain reaction (RT-PCR) conditions for the detection o f maspin expression in human breast carcinoma and assessed maspin's associa tion with the clinical behavior of primary breast cancers. Methods: Tumor specimens obtained from 45 primary breast cancer patients we re analyzed for maspin expression by a nested RT-PCR assay. Recurrence free survival was evaluated and correlated to maspin expression. Results: The maspin transcript was detected in 29 (64%) breast cancer speci mens whereas no expression was found in 16 (36%) cancer specimens. This exp ression was unrelated to any of the established prognostic factors. However , 6 out of 8 patients who developed distant metastasis (lymph nodes, lung, liver, bone, pleura) within 3 yr after their initial diagnosis showed no ma spin expression of the primary breast cancer (p < 0.05). Conclusions: The lack of maspin expression in breast cancer seems to be ass ociated with a short disease free survival and supports maspin's function a s an indicator of turner aggressiveness and metastatic potential. Nested RT -PCR is a sensitive method to determine maspin expression in human breast c ancer tissue. (C) 2001 The Canadian Society of Clinical Chemists. All right s reserved.