Lack of prognostic significance of survivin, survivin-ΔEx3, survivin-2B, galectin-3, bag-1, bax-α and MRP-1 mRNAs in breast cancer

The expression of transcripts for anti-apoptotic (survivin, survivin-ΔEx3, survivin-2B, galectin-3, bag-1 and bcl-2) and pro-apoptotic (bax-α) genes, and for multiple drug resistance related protein-1 (MRP-1) gene were investigated, using RT-PCR, in 106 breast tumour biopsies. Normal breast tissue was also analysed for comparative purposes. Overall, survivin, survivin-ΔEx3, survivin-2B, bcl-2, bag-1, galectin-3, bax-α and MRP-1 mRNAs were detected in 68, 54.7, 9.4, 78.4, 80.9, 98.9, 97.8 and 72.8%, respectively, of tumour specimens. Uniquely among the mRNAs analysed, the expression of bcl-2 correlated significantly with disease outcome, with bcl-2 expression indicative of favourable outcome in terms of both relapse-free survival and overall survival. This suggests that bcl-2 mRNA expression may be a key prognostic marker for breast cancer and that routine analysis of expression of this transcript should be considered. The results from this study suggest, however, that the expression of survivin, survivin-ΔEx3, survivin-2B, bag-1, galectin-3, bax-α and MRP-1 mRNAs cannot be considered as prognostic indicators of disease outcome for patients with breast cancer.