EGFR and neoplasm: Previous studies have reported several factors that are related to the clinical outcomes of PEM: sex [8], never-smoker [9, 10], epidermal growth factor receptor (EGFR) mutation [11], anaplastic lymphoma kinase (ALK) gene rearrangement [9–14], low tumor thymidylate synthase (TS) level [15–17], thyroid transcription factor-1 (TTF-1) expression [15, 16], low serum leptin level [18], and low tumor burden [11].