TFRC and neoplasm: Key advances include affinity tuning (equilibrium dissociation constants, K_D, in the 10-100 nM range) to balance transport efficiency with off-target risk; creation of dual-targeting systems (for example, heterodimers engaging TfR/TfR2); and engineering of pH-sensitive antibodies that exploit the acidic tumor milieu for conditional activation, improving specificity while reducing hepatotoxicity 23.