Now scientists are creating vaccines that aim to go further, teaching the immune system to intercept this type of brewing colon cancer before it turns into a full-fledged tumor. At least three potential Lynch syndrome vaccines are in development, including two in early clinical trials in the U.S. and a third beginning in Britain. Norton knew some of her mother’s relatives had also experienced colon cancer, but she was in her 40s before a gene test confirmed she has Lynch syndrome. But developing vaccines to prevent gene-caused cancer is more challenging than alerting the body to foreign intruders like a virus. Lynch syndrome affects about 1 in 279 people.