Gpnmb/osteoactivin: an indicator and therapeutic target in tumor and nontumorous lesions

Non-metastatic melanoma glycoprotein B (Gpnmb), a type I transmembrane glycoprotein, was first cloned and described in low-metastatic human melanoma and xenografts in 1995. Up to now a growing number of studies have confirmed that Gpnmb is expressed not only in numerous normal tissues but also at pathological sites and malignant tissues and often connected with the invasive and metastatic phenotypes, including breast cancer. Nowadays, immunotherapeutic approaches for cancer therapy, by which monoclonal antibodies (Mabs) target tumor specific antigens, have shown great potential. Glembatumumabvedotin, also called CR011-vcMMAE, is a Mab-drug conjugate which was developed for the treatment of Gpnmb-expressing cancers. Several phase I/II studies have confirmed the safety and activity of glembatumumabvedotin in patients with advanced/metastatic breast cancer and unresectable cutaneous melanoma. Moreover, increasing numbers of studies have supported the potential roles of targeting Gpnmb with glembatumumabvedotin in patients with recurrent osteosarcoma, uveal melanoma, ALS, Gaucher disease, pancreatic ductal adenocarcinoma etc. This review will summarize the latest understanding of Gpnmb in the aspects of diagnosis, progression and prognosis of pathological disorders and neoplasms, emphasizing the clinical advances in targeting Gpnmb-expressing malignancies.