Dennis Massimo, a 42-year-old construction estimator from West Chester, Pennsylvania, discovered he had Lynch syndrome after participating in the Penn Medicine BioBank. His sister, Lauren Massimo, an associate professor of Nursing at Penn and co-director of the University of Pennsylvania Frontotemporal Degeneration Center, encouraged him to join the BioBank in 2016 when he was undergoing a tonsillectomy.
In April 2025, Dennis received multiple calls from the BioBank that he initially ignored, believing them to be spam. When he finally answered, he learned that researchers had identified an MSH2 gene mutation in his DNA sample. He immediately contacted Lauren for guidance.
The discovery led to further clinical testing and confirmation that Dennis had Lynch syndrome. This hereditary condition increases the risk of developing certain cancers, particularly colorectal cancer. According to Penn Medicine genetic counselor Jessica Long, "MSH2 is one of the genes that helps the body prevent cancer from developing... When a mutation is present, the gene is unable to perform its normal role in cancer prevention." She explained that hereditary mutations affecting any one of four mismatch repair (MMR) genes cause Lynch syndrome.
Lynch syndrome affects about 1.2 million Americans and is recognized as the most common cause of hereditary colorectal cancer. Individuals with an MSH2 gene mutation face a lifetime risk of developing colorectal cancer between 30 and 50 percent—significantly higher than the general population's risk of less than five percent.
Although Dennis was three years younger than the recommended age for average-risk individuals to begin colonoscopy screenings, his diagnosis prompted earlier testing. A month after being notified by the BioBank, Dennis underwent his first colonoscopy.
"The scariest part of the whole thing was waking up from the colonoscopy in a private recovery room, with a box of tissues next to me," Dennis said. "I thought, ‘Oh my God, I’m in the grieving room.’"
Lauren accompanied her brother when they learned a tumor had been found and surgery would be necessary.
“Dennis had zero symptoms, and he was only 42—colorectal cancer was not on his radar,” Lauren said. “We thought he would get a baseline colonoscopy. We didn’t think they would find a tumor.”
Reflecting on his experience and early detection thanks to genetic screening through research participation, Dennis stated: “I found out when the cancer was stage III and not stage IV,” he said. “It really could have saved my life.”
