bcl-2/bax mRNA expression ratio as prognostic factor in low-grade urinary bladder cancer

Abstract
Apoptotic cell death represents an important mechanism for the precise regulation of cell numbers, and a defence mechanism against tumoral cells. bcl‐2 and bax genes are known to be involved in the control of apoptotic pathways; in particular, the ratio between bcl‐2 and bax represents a cell rheostat that is able to predict a cell's response toward life or death to an apoptotic stimulus. In the present study we investigated the role of bcl‐2 and bax gene expression in a panel of 37 low‐grade tumours of the urinary bladder, and correlated the expression of these genes to the prognosis of patients in a follow‐up of more than one year. We found that levels of bax expression higher than bcl‐2 in bladder tumours well correlates to a better outcome for patients. Early relapses are much more frequently observed in those patients whose tumours express more bcl‐2 than bax mRNA. We conclude that the bcl‐2/bax expression ratio may be considered as a marker for disease progression in low grade bladder tumours, independently of clinical staging and histological grading.