Dr. Stacy Norton lost her mother to colon cancer at a young age due to a genetic condition known as Lynch syndrome, which affects around 1 million Americans. This condition increases the risk of colorectal and other cancers due to a faulty gene passed down from a parent. Individuals with Lynch syndrome are advised to undergo regular colonoscopies to detect and remove precancerous polyps early.

To combat this high risk, scientists are developing vaccines designed to help the immune system prevent colon cancer before it becomes a tumor. Three such vaccines targeting Lynch syndrome are currently in development, with two in early trials in the U.S. and one beginning in the U.K. Dr. Eduardo Vilar-Sanchez of MD Anderson Cancer Center leads a promising study with plans for a larger scale test soon. Dr. Norton has participated in this research, fueling hope for her and her children.

The Role of Mismatch-Repair Genes

Lynch syndrome is caused by a mutation in mismatch-repair genes, which normally help correct DNA errors during cell division. This mutation impairs the body’s ability to fix abnormalities, often leading to tumor development before age 50. The average person’s risk for colorectal cancer is around 5%, but for Lynch carriers, it can soar up to 80% depending on the gene involved. Additionally, this syndrome heightens the risk for endometrial, pancreatic, stomach, ovarian, and certain skin cancers, as well as specific brain tumors. Genetic testing revealed Norton’s Lynch syndrome in her 40s, prompting annual colonoscopies and a precautionary hysterectomy that uncovered early-stage cancer.

Progress in Vaccine Development

Currently, only two vaccines exist that prevent cancer by blocking tumor-causing viruses: HPV and hepatitis B vaccines. Creating vaccines for genetically caused cancers, however, is more complex. The Lynch syndrome mutations result in unique proteins that can trigger the immune system. Research has shown promise, with a study involving a vaccine by Swiss biotech Nouscom. This vaccine trains the immune system against 209 specific abnormalities in Lynch-related precancers, which increased the activity of tumor-eradicating T cells. A year after vaccination, participants, including Norton, showed reduced precancerous growths.

Oxford University and Moderna have initiated trials for a similar vaccine using mRNA technology, inspired by its COVID-19 vaccine. Additionally, results are pending for a study by ImmunityBio, which is comparing its vaccine against a placebo, targeting different cancer markers.

Rising Young Adult Cancer Cases

Annually, about 158,000 people in the U.S. are diagnosed with colorectal cancer, the majority being over 50. However, cases in younger adults are rising. Lynch syndrome impacts 1 in 279 individuals, many of whom are unaware. More people might discover their condition through genetic testing, especially when cancer appears at an unusual age.

Standard U.S. guidelines recommend routine colorectal screenings starting at age 45. Regardless of age, individuals should seek medical attention if they experience symptoms such as blood in stool, unexpected changes in bowel habits, unexplained weight loss, and persistent abdominal pain.

Note: The Associated Press Health and Science Department has received support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation, but remains solely responsible for all content.