Therefore, studies on the prevalence of HER4 genomic aberrations, their effects on tumor biology and treatment response to targeted agents (e.g., ~21% of TKI-sensitive ERBB-mutant cancer cell lines of different tumor entities exhibit ERBB4 deletions177) and conventional chemotherapy, as well as on optimal treatment modalities, should be systematically performed in patients with NSCLC in the future, e.g., in the form of a world-wide registry trial similar to the eNRG trials. The gene discussed is ERBB4; the disease is cancer.