Dr. Strickler on Genomic Variants Detected by Liquid Biopsies in GI Cancers

John Strickler, MD, assistant professor of medicine at Duke University School of Medicine, gastrointestinal oncologist, Duke Cancer Institute, discusses genomic variants in patients with gastrointestinal (GI) cancers that can be detected by liquid biopsies.

In the GI cancers space, there are distinct scenarios in which liquid biopsies are already being utilized, including but not limited to cases where there is not enough tissue to test or when a re-biopsy of the tissue is not feasible. Additionally, it appears there are certain instances in which the sensitivity of a liquid biopsy confers an advantage over a standard tissue-based procedure, Strickler says.

Based on recent data, there may be genomic variants in the blood that may predict benefit from targeted therapies. For example, researchers have reviewed cases of HER2 amplification that suggest HER2 may be a potential targetable alteration that liquid biopsies alone can detect. In addition, a common challenge in GI cancers is when patients develop resistance to anti—EGFR therapy like cetuximab (Erbitux). Strickler notes that a liquid biopsy might be able to identify patients who could benefit from an EGFR antibody rechallenge. This entails detecting signals in the patient’s blood that signal that they may derive benefit from a therapy they progressed on.