Abstract
Increased expression of the epidermal growth factor (EGF) receptors, HER1 and HER2 are related to poor prognosis in most cancers studied. Recently, a high expression of the two remaining receptors of the EGF system, HER3 and HER4 has been related to a favourable prognosis. However, prognostic significance of HER1 and HER2 receptors in bladder cancer is controversial and the effect of the expression of different combinations of these receptors on patient survival is not well understood. Therefore, we examined the mRNA expression of all four EGF receptors with real-time polymerase chain reaction in biopsies from 88 patients with bladder cancer, where the survival was followed for a median of 38.5 months (range 1-117 months). Expression of HER1 and HER2 alone showed no correlation with survival. However, a high expression of HER1 together with high expression of HER3 and HER4 correlated to a better prognosis compared to the high expression of HER1 together with low expression of HER3 and HER4 (P=0.0006). Also, a significantly longer survival was observed in patients expressing high HER2 when coexpressed with high HER3 and HER4, as compared to the survival in patients with tumours expressing high HER2 but low HER3 and HER4 (P=0.0005). Our results suggest that the final outcome of patients with high HER1- and HER2-expressing tumours depends on the expression of HER3 and HER4.