FAP and neoplasm: To investigate the ability of a FAP-targeted conjugate of tubulysin B hydrazide (FL-L1-TubBH) to suppress tumor growth, MDA-MB231 tumor-bearing mice were randomized into untreated controls (administered with saline alone), mice treated with FL-L1-TubBH, and mice treated with FL-L1-TubBH in the presence of excess blocking ligand, FL (competition).