Gene expression assays as prognostic and predictive markers in early stage non-small cell lung cancer.

Lung cancer is the no.1 cancer killer in both men and women. Non-small lung cancer (NSCLC) comprises about 80% of all lung cancers and approximately one third of these patients are diagnosed at stage I-IIIA where treatment intention is curative (1). Due to a significant risk of relapse after surgery, adjuvant platinum-based chemotherapy is today recommended in NSCLC stage II-III (2-4). Prospective randomised data failed to show significant survival benefit from adjuvant chemotherapy in stage IB (except in an unplanned subset analysis of patients with tumour size >4 cm) and even a detrimental effect was observed in stage IA (2). The fact that 30-40% of stage I patients relapse after surgical resection alone, indicates, however, that some of these patients might benefit from adjuvant treatment.