Biomarkers in the era of individualized medicine
TNM staging has been a gold standard in the evaluation and treatment strategy for lung cancer. Preoperative anatomical discrimination of the exact range of tumor spreading is a key determinant for surgical resectability. In addition, postoperative pathologic evaluation of microscopic occult metastatic foci predicts the long-term prognosis. Classical prognostication based on the anatomical tumor extent has remained valid for decades despite the ongoing search for new prognostic markers. Many biomarkers have been suggested and validated, however, no single biomarker is as effective as TNM staging. These biomarkers represent the biological behavior of lung cancer cells; however, a sole biomarker without implication on treatment outcome has not been successful.