Enzyme-cleavable linkers, such as the widely used valine-citrulline (Val-Cit) linker in brentuximab vedotin and polatuzumab vedotin, exploit tumor-associated proteases like cathepsin B. These linkers are cleaved in lysosomes to release MMAE, often aided by self-destructible spacers, such as para-aminobenzyl carbamate (PABC) [32]. Here, CTSB is linked to neoplasm.