ERBB3 and small cell lung carcinoma: Consistently, FHD-286 treatment in two NE SCLC cell lines induced protein upregulation of ERBB family receptors ERBB2, ERBB3 and ERBB4 (Fig. 6D), and of NRG1 (Figs. 6E and S8B), a direct ligand and activator of ERBB proteins.