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from Medscape by Liam Davenport –
MUNICH — So-called liquid biopsies, which are based on standard blood draws, can identify molecular alterations that drive disease progression and hence drug resistance in almost 80% of patients, say researchers, who predict their findings that will change oncology practice during the next 5 years.
Speaking here at the 28th EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics, the researchers also showed that in comparison with standard tumor biopsy in gastrointestinal cancer patients, analysis of circulating tumor DNA (ctDNA) in plasma samples was able to detect additional mechanisms of resistance in more than 60% of cases.
“Overall, these data show how routine clinical implementation of liquid biopsy at the time of disease progression…can effectively identify important mechanisms of resistance and may offer certain advantages relative to tumor biopsies,” commented lead researcher Ryan Corcoran, MD, PhD, translational research director, Center for Gastrointestinal Cancers, Massachusetts General Hospital Cancer Center, Boston.
“Furthermore, liquid biopsies may better capture ‘tumor heterogeneity,’ or the evolution of distinct resistance mechanisms in different tumor cells in independent metastases in the same patient, which might be missed by a needle biopsy of a single tumor lesion,” he added.
Jean-Charles Soria, MD, chair of the scientific committee for the EORTC-NCI-AACR symposium and director of the Site de Recherche Intégrée sur le Cancer (SIRIC) Socrate project at Gustave Roussy Cancer Campus, Paris, France, described liquid biopsy as “a patient-friendly approach to obtaining critical insight into the intrinsic tumor biology.
“In this case, they have allowed rapid and robust identification of the mechanism of acquired resistance that can help clinicians to select further therapies for the patient,” he said.
Discussing the findings at a press conference, he said that liquid biopsies are going to “completely change the rules of engagement” for patient management and clinical practice.
Dr Soria continued: “I really think ― and I’m ready to bet ― that this is the most transformational thing that’s going to happen in oncology in terms of how it’s going to impact cancer clinical trials and cancer daily management for the next 5 years.”
Explaining the biological basis of the research, Dr Corcoran said: “Circulating tumor DNA is shed by tumor cells throughout the body into the bloodstream and can be isolated from a routine blood draw.
“Since tumor cells residing in different metastatic tumor lesions in the same patient can often evolve distinct mechanisms of drug resistance, liquid-biopsy analysis of circulating tumor DNA can frequently identify the simultaneous presence of multiple resistance alterations that would be missed by a single-lesion tumor biopsy,” he aded.
For the study he reported at the meeting, Dr Corcoran and colleagues studied 31 patients with molecularly defined gastrointestinal cancers, including 22 colorectal, seven biliary, and two gastroesophageal cancers. All of the patients had achieved a response or prolonged stable disease through targeted therapies.
