Cancer has cast a long shadow over Kevin Heyink’s family for generations. His maternal grandmother died of what was believed to be stomach cancer in at the age of 36, and seven of her eight siblings also succumbed to the disease. This pattern continued with his father, John Heyink, who had his entire colon removed in the 1980s due to cancer.
Like many of his relatives, Kevin Heyink, a 48-year-old police officer in Hamilton, Ontario, carries Lynch syndrome, an inherited genetic condition that significantly increases the risk of several types of cancer, particularly colorectal cancer. Individuals with Lynch syndrome have as much as an 80% chance of developing colorectal cancer in their lifetime, and it is estimated that one in every 280 Americans has the condition.
The family history led to regular screenings for Heyink, beginning with annual colonoscopies around age 20 and endoscopies every other year. He consistently had precancerous growths removed during these screenings. The constant vigilance took a mental toll, especially after his brother’s recent cancer diagnosis and the loss of other family members to the disease.
Driven by his family’s experience, Heyink sought out ongoing research into Lynch syndrome and discovered a clinical trial for a preventative cancer vaccine. He began participating in the trial at MD Anderson Cancer Center in Houston in .
The trial focuses on NOUS-209, an experimental vaccine designed to awaken the immune system to recognize and attack precancerous cells in individuals with Lynch syndrome. The results of the early-phase study were published last month in the journal Nature Medicine. The study found that the vaccine was safe and prompted an immune response in all participants, with some showing a stronger response than others.
Researchers also observed that participants who mounted a strong immune response had fewer precancerous lesions during colonoscopies one year after receiving the vaccine. Notably, no advanced polyps or lesions were found in the vaccinated population overall.
The University of Oxford is also starting work on a vaccine, called LynchVax, to prevent cancer in people with Lynch syndrome, with funding from Cancer Research UK. Lynch syndrome is caused by alterations in genes that control DNA repair, leading to an accumulation of errors and an increased risk of cancer. Approximately 1 in 400 people in the UK are estimated to have Lynch syndrome, but less than 5% have been diagnosed.
According to Dr. Raymond Kim, medical director of cancer early detection and the Bhalwani Familial Cancer Clinic at the Princess Margaret Cancer Centre in Toronto, the ability of researchers to demonstrate a specific immune response to peptides frequently found in Lynch syndrome-related cancers is promising. He emphasized that the research is still in its early stages, but the findings suggest they are on the right track.
Another clinical trial is underway for a competing vaccine, Tri-Ad5, which is given in combination with an immune-boosting agent. Currently, there are no approved vaccines to prevent hereditary cancers. Most cancer vaccines in development are therapeutic, designed to treat existing cancer or prevent recurrence, rather than preventative.
The biology of Lynch syndrome makes it an ideal target for a preventative vaccine. The syndrome is caused by mutations in mismatch-repair genes, which normally correct errors in DNA sequencing. When these genes aren’t functioning properly, errors accumulate, leading to the production of frameshift peptides commonly found on Lynch-induced tumors. The vaccine aims to train the immune system to recognize and eliminate cells displaying these peptides.
Heyink’s own colonoscopies have been clear since he began receiving the NOUS-209 vaccine. He previously had precancerous cells or lesions removed during annual screenings. He describes the feeling of a clear colonoscopy as “incredible,” given his family history.
Heyink’s experience highlights the impact of Lynch syndrome on families. His brother, Dave, died of adrenal gland cancer in at the age of 48. Another brother, Nathan, has survived stomach and liver cancer. Nathan and his wife face the added challenge of raising children who may also carry the Lynch syndrome gene.
The ongoing research offers a glimmer of hope for individuals and families affected by Lynch syndrome. While the NOUS-209 trial was designed to assess safety and immune response, the early findings are encouraging and pave the way for larger, randomized control trials to test the vaccine’s efficacy. The development of preventative vaccines for hereditary cancers represents a new frontier in cancer prevention.
