Due to the high affinity to HER2, MCLA-128 docks on HER2 and blocks the formation of HER2/3 heterodimers and NRG1-fusion binding to HER3 simultaneously, thus inhibiting tumor cell proliferation (de Vries Schultink et al. 2020; Geuijen et al. 2018; Editorial 2019). This evidence concerns the gene ERBB3 and neoplasm.