Furthermore, many published studies have been conducted on pre-selected cohorts of NSCLC patients, suffering from consequent bias in terms of the frequency of EGFR mutations or in other driver oncogenes considered as potential prognostic factors in early-stage NSCLC such as the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene [13,14]. Here, EGFR is linked to non-small cell lung carcinoma.