ERBB3 and neoplasm: In particular, the seemingly modest but transient attenuation of tumor growth in mice by ‘empty’ HPK particles (i.e., H-NS) may be consistent with the temporary attenuation of HER3 signaling observed at early time points after receptor binding in our recent study (21), which in turn may be supported by the robust sequestration of HER3 by HPK particles observed in the present study, as well as the subsequent PB-mediated disruption of endosomes.