Liquid biopsy in cancer management

The ctDNA is released by tumor cells of the primary tumor, circulating tumor cells (CTCs) or metastases. [...]ctDNA concentration fluctuates and data may be inconclusive; affected by tumor size or disease stage, for example. Clinical data have demonstrated that very low amounts of ctDNA (less than 10 copies per 5 ml plasma) or up to 100-fold concentrations can be detected in a patient specimen. [...]liquid biopsy assays require highly sensitive detection methods to identify individual tumor-derived molecules in a background of unmutated DNA. The half-life of circulating cell-free DNA is less than one hour. [...]the sample collection and tube handling processes also impact the outcome and therefore the diagnostic result.