Additionally, targeting heregulin or neuregulin 1 (NRG1), which activates the HER3 receptor, has been effective in combination with trastuzumab emtansine (T-DM1) and pertuzumab, inhibiting the NRG1/HER3 signaling pathway, leading to increased tumor suppression and extended tumor regression [111]. The gene discussed is NRG1; the disease is neoplasm.