ESR1 and anemia (phenotype): Nineteen indicators relevant to the anemia prediction model for patients with osteosarcoma after chemotherapy were identified, including Gender, Surgery, LYM, MO, LYM%, BLT, TP, ALB, CA, CREA, APTT, FIB, D‐dimer, CRP, ESR, PCT, IgA, CEA, and CA.153.