RUNX2 and osteosarcoma: Activation of DRD1 has been demonstrated to induce osteogenic differentiation by stimulating the phosphorylation of extracellular regulated protein kinases 1/2 (ERK1/2) and thus enhance Runx2 transcriptional activity.[41] In the bone metastasis model, the DRD1 agonist exerts an inhibitory effect on osteoclasts by regulating NFATc1 through increasing p‐eIF2a levels.[42] In the osteosarcoma model, DRD1 inhibits osteosarcoma cell proliferation by downregulating ERK1/2 and PI3K‐Akt signaling.[43] However, the effect of DRD1 on osteoblasts in GC‐associated ONFH has not been reported.