RARB and osteosarcoma: Possibly due to the heterogeneity of osteosarcoma cell lines, some osteosarcoma cell lines were only sensitive to high concentrations of certain chemicals; this was true for U2OS cells treated with the Rev-Erba agonist (Fig. 2D), HOS-MNNG cells treated with the PPARg antagonist (Fig. 2F) and Saos-2 cells treated with the RARb antagonist (Fig. 2I).