In this report, we investigate the mRNA expression of HER3, HER4, HRG1, HRG2, HRG3 and HRG4 genes, including the splice variants from HRG1 and HRG2, in biopsies from 88 bladder cancer patients using the real-time RT–PCR method. Here, NRG4 is linked to urinary bladder carcinoma.