EGFR and chronic obstructive pulmonary disease: The treatment of COPD with tanshinone IIA involves multiple signaling pathways and biological processes, and its binding to the key targets of EGFR, CASP3, MMP9, NFKB1, SRC, and HSP90AA1 may be one of the important mechanisms of its action, which provides new theoretical ideas for the subsequent treatment of COPD with tanshinone IIA.