RGS4 and osteosarcoma: RGS4 has recently been studied as a tumor promoter in glioblastoma (Bao et al., 2020; Guda et al., 2020), non-small cell lung cancer (He et al., 2019) and osteosarcoma tumors (Liu et al., 2020), and is reported to be a potent driver of cell proliferation, invasion and migration.