Scientists are currently testing innovative vaccines designed to teach the immune system to intercept brewing colon cancer before it develops into full-fledged tumors, according to reports from Apnews. At least three potential vaccines targeting Lynch syndrome are in development, which includes two in early clinical trials in the United States and a third beginning testing in Britain.
New Vaccines Enter Testing to Intercept Lynch Syndrome Colon Cancer
Dr. Stacy Norton, a 59-year-old doctor from Houston Methodist Willowbrook Hospital, participated in testing one of these experimental shots. Norton was only seven years old when her mother died of colon cancer, part of a family history featuring aggressive tumors at young ages. Norton is among an estimated one million Americans who carry Lynch syndrome, an inherited faulty gene that significantly increases the risk of colorectal cancer and other malignancies.
Understanding Lynch Syndrome and Inherited Risks
Lynch syndrome is caused by an inherited genetic mutation involving mismatch-repair genes, which function as cellular spellcheckers to fix DNA mistakes during cell multiplication. When someone has Lynch syndrome, one of these genes fails to work properly, making it difficult for the body to stop the buildup of abnormalities that can lead to tumors, frequently before the age of 50.
While the average person has a 5% lifetime risk of developing colorectal cancer, a Lynch carrier’s risk can reach as high as 80% depending on the specific faulty gene inherited. Carriers also face elevated risks for endometrial or uterine cancer, stomach, pancreatic, ovarian, and certain skin cancers, as well as a type of brain tumor that caused the death of Norton’s sister at age 25. Because of these heightened dangers, carriers are typically urged to undergo yearly colonoscopies to find and remove precancerous growths known as polyps. If a vaccine eventually proves successful, Eduardo Vilar-Sanchez of the MD Anderson Cancer Center noted, patients perhaps they won’t have to have a colonoscopy every single year for the rest of their lives.
Early Vaccine Trials Show Promising Immune Responses
Developing vaccines to prevent gene-caused cancer poses a distinct challenge compared to traditional shots like HPV and hepatitis B, which block tumor-causing viral infections. Lynch-fueled growths tend to accumulate hundreds of mutations that generate novel proteins not produced by normal cells. Vilar-Sanchez explained that researchers can train the immune system to recognize those unique proteins.
In an initial study published in Nature Medicine, Norton and 44 other Lynch carriers tested a vaccine developed by Swiss biotech firm Apnews. The vaccine trains the immune system to spot 209 abnormalities found in Lynch-caused precancers. The treatment successfully revved up tumor-eliminating T cells, and follow-up colonoscopies a year later revealed fewer precancerous growths and no advanced polyps. For the first time since 2014, Norton’s own post-vaccination colonoscopies at one and two years were entirely polyp-free. She also participated in a subset of study participants given a booster shot a year later, with additional data expected in the fall.
Broadened Trials and Future Research Outlook
Researchers are expanding their evaluation of these preventative approaches. Vilar-Sanchez expects a larger study to begin early next year. Meanwhile, researchers at Oxford University are beginning initial testing of a similar strategy to attack Lynch-spurred precancers using a vaccine created by Massachusetts-based Globalnews, leveraging the mRNA technology utilized in its COVID-19 shot.
Dr. John Marshall, a Georgetown University oncologist and adviser to the Colorectal Cancer Alliance who was not involved in the research, raised the question of whether scientists can further stimulate the immune system to keep pace with Lynch syndrome-spurred tumor formation. Assessing the initial findings, Marshall stated, This early paper suggests that yeah, maybe we can.
