Abstract
More than 1 million people dies worldwide due to lung cancer which is the first most incident cancer in males and the third in females. Only early diagnosis makes possible to achieve long-lasting remission or even cure the disease. Unfortunately, no tumour marker to achieve this goal has been identified, yet. One of putative lung cancer markers is free circulating tumor DNA. Its concentration seems to be related to cancer burden. Moreover, it can be subjected to mutational status analysis allowing for introduction of targeted treatment. This led to the idea of liquid biopsy which can substitute for a standard biopsy not feasible in certain clinical circumstances. Assessment of cell free tumour DNA can also inform about progression/recurrence of cancer and may have a prognostic value. Therefore, the aim of this article is to review on free circulating DNA as a potential marker in lung cancer.