Our previous studies found that the inhibition of STAT3 expression could reverse the chemosensitivity of osteosarcoma cells to doxorubicin, the STAT3 gene was chosen as a candidate target of miR-506-3p for the study of the molecular mechanism of reversing doxorubicin chemoresistance in drug-resistant osteosarcoma cells. The gene discussed is STAT3; the disease is osteosarcoma.