Liquid biopsy in early detection and monitoring of CNS metastases.

The treatment of human cancer has shifted toward a precision-medicine paradigm that increasingly relies on the genomic annotation of each patient's tumor tissue. This trend is supported by the observation that treatment response is often dependent on tumor mutations in targeted pathways, by the discovery of particular drug-resistance mutations in tumors that resume growth during therapy, and by the recent association between effective immunotherapy and tumor-specific missense mutations. Early detection of cancer and accurate characterization of tumors improve patient outcomes, so research into noninvasive means of obtaining this information is of significant clinical relevance. Furthermore, the outgrowth of drug-resistant tumor cell clones during therapy can limit the clinical relevance of the initial tumor profile and has motivated the development of technologies that can track the evolution of the cancer genome in accessible body fluids.