Per current understanding, HER3 overactivation by NRG1 fusion proteins represents the primary driver of growth and survival in tumors harboring NRG1 fusions [17–19], and the presence (vs. absence) of NRG1 fusions has been shown to correlate with worsened survival outcomes in lung cancer, including shorter overall survival and disease-free survival [20]. This evidence concerns the gene ERBB3 and lung cancer.