Variable levels of bcl-2, bcl-X and bax mRNA in bladder cancer progression

We investigated the expression of the anti-apoptotic genes bcl-2 and bcl-X and the pro-apoptotic gene bax in bladder tumors and normal samples from urinary bladder, using RT-PCR analysis. Bcl-2 mRNA was not detected in any of the normal samples, while it was found expressed in 66% of the low stage tumors and in 100% of the high stage tumors. Bax expression had an inverse progress, being present in 62% of the normal tissues examined, in 16% of the low stage tumors and in 14% of the high stage. Bcl-X gene expression was quite variable among all samples (37% in normal tissues, 50% in the low stage tumors and 14% in the high stage), bcl-X mRNA was only found in the isoform bcl-X-L, with anti-apoptotic functions, whereas no sample expressed the isoform bcl-X-S, which is known to suppress bcl-2 functions. Most samples expressing bcl-2 did not express bcl-X, and vice versa. These results, besides confirming the potential role of these genes in the pathogenesis of low stage bladder cancer strengthen the hypothesis concerning their possible interaction in the progression of disease.