Detection of folate receptor–positive circulating tumor cells by ligand-targeted polymerase chain reaction in non-small cell lung cancer patients

Currently circulating tumor cells (CTCs) represent attractive predictive and prognostic biomarkers. CTCs may be used to evaluate the treatment efficacy, to assess prognosis, to predict the risk of recurrence in several cancers, including lung cancer (1). CTCs are extremely rare in the bloodstream approximately with a frequency of 1 CTC per 10⁶–10⁷ leukocytes, therefore highly specific and sensitive methods are required to their detection (2).