RESUMO
Molecular techniques can be very useful in detecting a patient's tumor to guide treatment decisions is increasingly been applied in the care and management of cancer patients. Circulating tumor DNA (ctDNA) containing mutations can be identified in the plasma of cancer patients during the course of the disease. As a non-invasive "liquid biopsies",ctDNA is a potential surrogate for the entire tumor genome. The use of ctDNA might help to determine the disease prognosis,monitor disease progression,monitor the molecular resistance and monitor the tumor heterogeneity. Future developments will need to provide clinical standards to validate the ctDNA as a clinical biomarker and improve the reproducibility and accuracy,in order to be better exploited for personalized medicine.