Clinical utility of circulating tumor cells in non-small-cell lung carcinoma: are we there yet?

Over 140 years ago, the discovery was made that tumor cells morphologically resembling those in the primary tumor of a patient can be found in the patients’ circulation (1). The notion that these cells in the circulation are probably shed from the patient’s primary tumor was confirmed upon advancement in cytogenetic techniques that demonstrated that these circulatory cells can also carry genetic abnormalities detected in primary tumors (2).