Official websites use. Share sensitive information only on official, secure websites. Address correspondence to Bert Gold, Ph. This document may be redistributed and reused, subject to certain conditions. Diagnosing and screening for tumors through noninvasive means represent an important paradigm shift in precision medicine. In contrast to tissue biopsy, detection of circulating tumor cells CTCs and circulating tumor nucleic acids provides a minimally invasive method for predictive and prognostic marker detection.
This allows early and serial assessment of metastatic disease, including follow-up during remission, characterization of treatment effects, and clonal evolution. However, more trials are required to validate the clinical utility of precise molecular markers for a variety of tumor types. This review focuses on the clinical utility of CTCs and ctDNA testing in patients with solid tumors, including somatic and epigenetic alterations that can be detected.
A comparison of methods used to isolate and detect CTCs and some of the intricacies of the characterization of the ctDNA are also provided. Such a tumor doubles once every days and weighs just more than half a gram. They can remain unitary in the vasculature, cluster together as they disseminate, or lodge themselves in new tissues to form metastases.
Whatever the path of circulating tumor cells CTCs , they potentially hold valuable information about tumor composition, invasiveness, drug susceptibility, and resistance to therapy. Each of these tumor characteristics is potentially amenable to molecular and cellular characterization through its isolation. An average metastatic carcinoma patient has between 5 and 50 CTCs for approximately every 7.
Such markers have become available in the past decade. In that time frame, new technologies have, for the first time, allowed the isolation of CTCs from patient blood samples. In more recent devices, CTC isolation techniques have depended on antibodies against epithelial cell adhesion molecule EpCAM , a protein that protrudes from the outer surface of CTCs, but not healthy blood cells Table 1. This table is an updated version of Table 2 first published by Parkinson et al. That platform uses EpCAM antibodies attached to magnetic beads to isolate tumor cells in conjunction with proprietary CellSave venipuncture tubes that preserve CTC structure.
