PTPRG and plasma cell myeloma: Of note, it has been shown that R5 receptor–type PTP inhibitors with PTPRG activity (NAZ2329: cell-permeable, allosteric; SCB4380: competitive, effective with liposomal delivery) suppress tumor growth and stem-like properties in glioma models (44); and murine monoclonal antibodies against the PTPRG ectodomain have been generated and used on CML samples, demonstrating surface accessibility and a plausible route for myeloma-directed biologics (12, 37).