An estimated one in every 288 people has Lynch syndrome. “It’s about 1 million people in the United States,” says Eduardo Vilar-Sanchez, M.D., Ph.D.

This hereditary condition increases the likelihood of developing several cancers. “Although widely recognized for its link to colorectal and endometrial cancers, Lynch syndrome can generate other tumors as well,” says Vilar-Sanchez. He notes that ovarian, stomach, small bowel, brain...