It is well established that activation of cellular genes may trigger uncontrolled cell growth and cancer development. Previous reports suggest that the epidermal growth factor receptor (EGFr), c-erbB2/neu and int-2, fibroblast growth factor-3, may be implicated in the development of benign prostatic hyperplasia (BPH). Using the polymerase chain reaction technique, we have assessed the amplification and expression of these molecular markers in 30 prostate samples from patients with BPH as well as from 5 normal donors. We detected mRNA over-expression of EGFr and c-erbB2/neu in 36% and 63%, respectively, of the BPH samples, but no gene amplification was found. No amplification or over-expression of int-2 was detected in any of the samples analyzed, suggesting that int-2 is not involved in BPH. Our results thus suggest a role for EGFr and c-erbB2/neu but not for int-2 in the development of BPH.