CRP and infection: It is noteworthy to underline that in the setting of mNSCLC an increase of infection biomarkers, such as PCT, CRP and ESR, cannot be considered very specific for active infections, as these biomarkers may be related to the malignancy itself or to concomitant smoke-associated bronchopulmonary chronic disease (32), although PCT can be considered more specific and aid in the differential diagnosis between infectious fever and tumor fever (50, 51).