ERBB2 and osteoporosis: From the WikiPathways analysis, ERBB signaling pathway (Fig. 7) and mitogen-activated protein kinase (MAPK) signaling pathway (Fig. 8) and related targets, including ErbB, ERBB2, EGFR, mitogen-activated protein kinase 8 (MAPK8) were revealed (Table 3), suggesting the importance of the targets of EGFR and MAPK8 ERBB and MAPK signaling pathways for VitD in its actions on COVID-19 and osteoporosis.