 RGMB is a glycosylphosphatidylinositol (GPI)-anchored member of the repulsive guidance molecule family (see also RGMA and RGMC) and contributes to the patterning of the developing nervous system.There is a potential association between RGMs and cancer bone metastasis, as RGMs coordinate bone morphogenetic protein (BMP) signaling.RGMB may act as a negative regulator "in vitro" in breast cancer and prostate cancer through BMP signalling.