Soluble PD-1 was identified as a good prognostic indicator in EGFR-mutated non-small cell lung cancer patients which may suggest that the surgery-induced decrease in circulating levels of PD-1 in post-operative patients in this study may be detrimental to anti-tumour immunity highlighting the immunosuppressive nature of surgery in the immediate post-operative period (28). This evidence concerns the gene EGFR and non-small cell lung carcinoma.