Liquid biopsy helps us to know the present tumour dynamics, by its molecular characterization, keeping a track on tumour heterogeneity and metastasis. This reduces the need of repeated biopsies which are often rendered impractical and possess a great risk to patients.

Personalised medicines seem to address and suit cancer patients the most; to achieve this, molecular characterization of the tumour needs to be analysed, which is provided by liquid biopsy. Liquid biopsy aids in diagnosing and monitoring a tumour, and also help in tracking any kind of treatment resistance. It allows us to know the genetic make-up of a tumour, and being a non-invasive procedure, it could be performed over and over again, eliminating the need of traditional biopsy.

CTCs(circulating tumour cells) are shed by the primary tumour and then enter the circulation. Dying tumour cells undergoing necrosis or apoptosis, shed their DNA into the circulation referred to as Circulating tumour DNA (ctDNA). Recent technological advances in the field of CTC including CTC microchips and quantitative reverse transcriptase PCR have improved the detection procedures, whereas the advances in sensitivity and accuracy of DNA analysis has helped immensely to detect and identify ctDNA. This article provides an overview of the various methods employed in the field of liquid biopsy, viz. CTC, ctDNA, exosomes, and their relation in the screening and monitoring of oral cancers.