Update on emerging biomarkers in lung cancer

In 2004, several papers reported that the presence of epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) predicted the response of those tumors to EGFR tyrosine kinase inhibitor (TKI) therapy (1-3). This news was followed by prospective clinical trials that confirmed better outcomes for NSCLC patients selected for gefitinib and erlotinib therapy on the basis of actionable EGFR mutations (4-8). This was followed by the discovery that the presence of anaplastic lymphoma kinase (ALK) gene rearrangements predicted the response of NSCLC to the ALK TKI crizotinib (9). The Food and Drug Administration (FDA) subsequently approved crizotinib for the treatment of advanced NSCLC harboring the ALK gene rearrangement with the Vysis ALK Break Apart FISH Probe Kit as a Companion Diagnostic for testing for the ALK translocation (10)