An estimated 1 million Americans carry Lynch syndrome, an inherited faulty gene that spikes the lifetime risk of colorectal cancer up to 80%, according to data cited by MD Anderson Cancer Center researchers. Patients managing this diagnosis often face grueling schedules of annual colonoscopies. Now, researchers are testing preventative cancer vaccines designed to train the immune system to intercept brewing tumors before they fully form.
How Cancer-Preventing Vaccines Target Faulty Genes
Everyone possesses mismatch-repair genes that act as cellular spellcheckers, fixing DNA mistakes that occur when cells multiply. For individuals with Lynch syndrome, one of these vital genes fails to function properly, causing dangerous abnormalities to build up and trigger tumors, often before age 50. Dr. Eduardo Vilar-Sanchez of the MD Anderson Cancer Center explains that Lynch-fueled growths typically accumulate hundreds of mutations, generating novel proteins that normal cells do not make.
Scientists are leveraging this biological quirk to develop preventative shots. In a recent initial study reported in Nature Medicine, 45 Lynch carriers tested a vaccine developed by Swiss biotech firm Nouscom. The vaccine successfully trained the immune system to spot 209 specific abnormalities found in Lynch-caused precancers, revving up tumor-eliminating T cells.
Did You Know?
While the HPV and hepatitis B shots protect against tumor-causing viruses, developing vaccines to prevent gene-caused cancers like those driven by Lynch syndrome presents a much higher scientific hurdle.
Patient Trials Show Promising Results Against Precancerous Polyps
Dr. Stacy Norton knows the devastation of Lynch syndrome intimately. Norton lost her mother to colon cancer when she was just 7 years old and later lost her sister to a brain tumor at age 25. Genetic testing in her 40s confirmed she also carried the faulty gene, prompting her to undergo yearly colonoscopies and a precautionary hysterectomy that uncovered early-stage uterine cancer.
When the opportunity arose, Norton rolled up her sleeve to help test the Nouscom vaccine. One and two years following vaccination, her routine colonoscopies were completely polyp-free for the first time since 2014. Dr. John Marshall, a Georgetown University oncologist and adviser to the Colorectal Cancer Alliance who was not involved with the study, noted that the early findings suggest researchers can successfully stimulate the immune system to keep pace with tumor formation.
Following these encouraging results, Vilar-Sanchez expects a larger clinical trial to launch early next year. Meanwhile, other institutions are advancing alternative vaccine technologies. Oxford University researchers are initiating early testing of a similar preventive approach using an mRNA vaccine developed by Moderna. Additionally, scientists are awaiting results from a slightly larger study testing a Tri-Ad5 vaccine from California-based ImmunityBio against a placebo.
Screening Guidelines and What Experts Recommend
Colorectal cancer diagnoses impact roughly 158,000 people in the U.S. each year. While the majority of patients are over 50, cases among younger adults continue to rise. Because genetic testing is increasingly discussed among families with histories of early-onset tumors, more individuals are discovering they have Lynch syndrome, which affects roughly 1 in 279 people, according to Vilar-Sanchez.
For the general population, current U.S. guidelines recommend beginning routine colorectal cancer screenings at age 45 via colonoscopy or alternative testing methods. Health experts advise individuals of any age to seek a medical evaluation if they experience symptoms such as:
- Blood in the stool or rectal bleeding
- Changes in bowel habits, including persistent diarrhea, constipation, or narrowing of the stool lasting more than a few days
- Unintended weight loss
- Abdominal pain or cramping
Frequently Asked Questions
What is Lynch syndrome?
Lynch syndrome is an inherited genetic condition caused by a faulty mismatch-repair gene. It significantly increases a person’s lifetime risk of developing colorectal, uterine, and several other types of cancer.
How do preventative cancer vaccines work for Lynch carriers?
These vaccines train the immune system to recognize novel proteins and abnormalities generated by precancerous cells, allowing T cells to intercept and eliminate the growths before they develop into full-fledged tumors.
When will the next clinical trials begin?
Researchers like Dr. Eduardo Vilar-Sanchez expect larger clinical studies evaluating these preventative vaccines to launch as early as next year.
What are the standard screening recommendations for colorectal cancer?
U.S. guidelines recommend that average-risk adults begin routine colorectal cancer screening at age 45 using a colonoscopy or other approved screening tests.
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