Blood test reveals more vivid GI cancer gene mutations

Blood test versus a tumor biopsy: Which reveals more gene mutations in the diagnostics and treatment of gastrointestinal cancer?  New research from the Dana-Farber Cancer Institute in Boston points very much to the former.

Their research found that their new blood diagnostic gave a much bigger picture of the various gene mutations that fueled the disease. The findings, presented at the American Association for Cancer Research annual meeting in Washington, D.C., should help supercharge the push for personalized medicine, where researchers identify which drug works best for a patient's particular cancer and then give a targeted and (hopefully) more effective treatment as a result.

The team looked at patients with metastatic gastrointestinal stromal tumors in a phase 3 clinical trial of oral regorafenib (Bayer's drug also known as Stivarga). Researchers compared both approaches--a blood diagnostic to DNA analysis of a traditional tumor biopsy. The goal: to see whether traditional biopsy analysis or the new blood test would work better to detect secondary gene mutations for KIT, after the cancer became resistant to the drugs imatinib and sunitinib. BEAMing technology won hands down, detecting secondary KIT mutations in nearly half of the blood samples. And half of those had several kinds of mutations. Testing of tissue samples, by contrast, only detected those mutations 12% of the time.

The results point to the promise of a supercharged blood test to evaluate a cancer's genetic structure to the point where targeted treatments become more feasible. The test, which uses BEAMing Digital PCR technology developed by Maryland's Inostics, expands copies of tumor DNA circulating in the bloodstream. Researchers from Cedars-Sinai Medical Center and UCLA pursued a similar idea with their NanoVelcro Chip. It's designed to take a "liquid biopsy" of circulating tumor cells directly from the blood, after which whole exome sequencing can both spot and detail a cancer cell's genetic mutations with precision.

George Demetri, Dana-Farber's senior vice president for experimental therapeutics, worked with a team of researchers to develop the new blood test, which helped bring regorafenib though the FDA approval finish line. He said in a statement that traditional DNA biopsies can fall short, reducing the chance for success of personalized drug treatment. But the blood test, he added, should give clinical trials for targeted cancer drugs a big boost. What's more, he added, the blood test should help advance everyday cancer care to make it "more precise and personalized."

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