Mini-Review: GARP, a Putative Potential Molecule in Tumor Immunosuppressive Environment

Abstract

Glycoprotein A Repetitions Predominant (GARP), also known as leucine-rich repeats containing 32 (LRRC32), is a transmembrane protein that presents latent TGF-β1 on the surface of regulatory T cells (Tregs) and modulates its activation in tumor immunosuppressive environment. Tregs are immunosuppressive immune cells that play an important role in tumor development and progression. Inhibition of Treg function is considered to be an effective strategy for antitumor therapy. In addition to its expression in Tregs, GARP has been recently found to be highly expressed in a few types of human solid tumor tissues, yet the role of its expression in tumor tissues or cells remains unknown. Most previous studies on GARP have focused on GARP function in Tregs and the role of GARP in latent TGF-β1 activation. The present review provides an up to date overview of GARP expression and its potential role in tumor cells and tissues.