MDM2 and osteoporosis: When the core targets were screened by the topological features31 and twice the average node degree as the screening criteria (degree ≥ 10.2), epidermal growth factor receptor (EGFR), AR, ESR1, MAPK8, MDM2, EZH2, ERBB2, and MAPT were identified as the core targets of VitD, osteoporosis, and COVID-19 (Supplementary Table S15).