NRG1 and breast cancer: The discovery ofNRG1fusion dates back to 1997 in the breast cancer cell line MDA-MB-175, where it was identified as a tumor-specific DOC4-NRG1 transcript that promotes tumor cell proliferation.23In lung cancer,NRG1gene fusion results in the overexpression of the EGF-like domain of NRG1 on the cell surface.