ERBB3 and cancer: Due to the implication of HER3 in various cancers, several structures of the HER3 ECD in complex with antibody Fab fragments, such as 3379, RG7116, MOR09825 and MF3178, are available (PDB entries 5cus, 4leo, 4p59 and 5o4o; Mirschberger et al., 2013 ▸; Lee et al., 2015 ▸; Garner et al., 2013 ▸; Geuijen et al., 2018 ▸).