Since some patients with ALS appear to have dampened ERBB4/ALS19 function in tissues of the central nervous system [8, 9, 22], either due to germline mutations or via other mechanisms [11, 37], it seems unexpected that even potent pan-ERBB/HER kinase inhibitors such as neratinib and dacomitinib that are used in the clinic to treat cancer do not have significant neurologic side effects, even though these pan-ERBB2/HER inhibitors attenuate ERBB4/HER4/ALS19 function, and can be continued for months or years for cancer treatment [84, 85]. This evidence concerns the gene ERBB2 and cancer.