Harmonization of Epidermal Growth Factor Measurements: Paving the Way of Finding A Biomarker in Non-Small Cell Lung Cancer

Abstract

Literature reports only a few contradictory findings regarding the capacity of serum EGF concentrations to differentiate between healthy individuals and patients suffering non-small cell lung cancer (NSCLC). Therefore, the possible diagnostic capacity of serum EGF levels, suggestive of dependency on this growth factor in NSCLC patients/tumors and hence indicative of possible response to therapies directed to EGF/EGFR, is controversial. Inconsistencies likely derive from the lack of harmonization and even standardization in methodologies for blood and sera processing. This manuscript is a mini-review of a recently published study, where the control of the key factors that influence the concentration of EGF in serum, along with the normalization of EGF concentrations by platelets count, allowed to clarify the diagnostic value of serum EGF levels. Several EGF-related variables were identified as potential biomarkers in NSCLC, particularly those normalized by platelets, which highlighted the differences between patients and controls. Additionally, the study revealed that NSCLC patients differ from healthy individuals not by the total stock of EGF, but by its higher accessibility to serum. The increase in free/accessible EGF in blood circulation is probably relevant to the biology of NSCLC, most likely because it reflects a higher accessibility to this tumoral growth factor.