A retrospective analysis, performed by the Hellenic Co-operative Oncology Group (HeCOG), in samples from patients with histologically confirmed NSCLC, who had been treated within HeCOG-affiliated centres from March 2000 through December 2012, were centrally evaluated for the presence of KRAS and EGFR mutations. All patients had available clinicopathological data at diagnosis. Formalin-fixed, paraffin-embedded tissue blocks were retrospectively retrieved from the HeCOG tumor repository. Cytologic material was prospectively submitted for genotyping in more recent years (2010-2012).
