ERBB4 and esophageal squamous cell carcinoma: Three out of 5 novel mutations are within ERBB4 functional domain; therefore, we constructed the three ERBB4 mutants within domain and found that over-expression of ErbB4-V391I or ErbB4-P377R increased the basal ErbB4 phosphorylation compared with that of ErbB4 wild type in HEK293T and ESCC cell lines (KYSE150 and KYSE180)26 (Fig. 1e, Supplementary Fig. 4d).