ERBB2 and neoplasm: Although the difference between H32 IgG (KD = 2.7 × 10−8), 61 IgG (KD = 2.7 × 10−8), and 75 IgG (KD = 2.7 × 10−8) in affinity against HER2 was not obvious15, the inverse correlation between affinity and in vivo tumor uptake, either derived from images or obtained from biodistribution studies, was also noticed (Figs 5 and 6).