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

BACKGROUND

Maspin (mammary serpin) is a relatively novel serine protease inhibitor with tumor suppressing function in breast cancer. Maspin expression was found in normal breast epithelial cells, but was decreased during tumor progression. Only a few systematic analyses of this phenomenon have been undertaken so far. In this study we developed specific nested reverse transcription polymerase chain reaction (RT-PCR) conditions for the detection of maspin expression in human breast carcinoma and assessed maspin's association with the clinical behavior of primary breast cancers.

METHODS

Tumor specimens obtained from 45 primary breast cancer patients were 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 specimens whereas no expression was found in 16 (36%) cancer specimens. This expression 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 maspin expression of the primary breast cancer (p < 0.05).

CONCLUSIONS

The lack of maspin expression in breast cancer seems to be associated with a short disease free survival and supports maspin's function as an indicator of tumor aggressiveness and metastatic potential. Nested RT-PCR is a sensitive method to determine maspin expression in human breast cancer tissue.