CXCR4 and neoplasm: In contrast to small molecule and peptide inhibitors of CXCR4, ulocuplumab, as well as another IgG4 CXCR4 antibody, LY26245587, and an IgG1 CXCR4 antibody hz515H7 [68], can induce tumor cell death via a mechanism reminiscent of PCD, similarly to PF-06747143.