EGFR and chronic obstructive pulmonary disease: Clinical characteristics were collected and included age, sex, smoking status, histology, clinical stage, epidermal growth factor receptor(EGFR) mutational status, chronic obstructive pulmonary disease (COPD) concomitant state, absolute neutrophil count(ANC), absolute lymphocyte count (ALC), absolute monocyte count (AMC), red blood cell count (RBC), and platelet count (PLT).