LRRC15 and osteosarcoma: Studies in osteosarcoma and rhabdomyosarcoma have identified 11 and 9 surface proteins, respectively, including FGFR4, MEGF10, CD276, AGRL2, GPC4, JAM3, CADM2, NCAM1, L1CAM, MT1-MMP, MRC2, CD276 and LRRC15 [224, 225].