The expression level of HRG2β (P⩽0.001) and HRG4 (P⩽0.001) was also altered in biopsies classified as T1 in comparison with Ta (Figure 1F and H), which shows an early loss of HRG2β and HRG4 during bladder cancer progression. The gene discussed is NRG4; the disease is urinary bladder carcinoma.