Lower lip holds clue to hereditary colon cancer syndrome
Abnormally dense blood vessel growth in the mouth appears to be associated with familial adenomatous polyposis (FAP), an autosomal dominant disease that causes hundreds of colorectal adenomas in teenagers and progresses to colorectal cancer if colectomy is not performed.
FAP is normally diagnosed with costly DNA tests and colonoscopies, and sometimes goes unnoticed until cancer develops. In 2003, Italian researchers reported that a similar genetic condition—hereditary nonpolyposis colorectal cancer (HNPCC)—was linked to a greater complexity of blood vessels in the oral mucosa. Acting on this information, a team at Johns Hopkins School of Medicine in Baltimore, Maryland, and The Catholic University of America in Washington, DC, developed a device that allowed a direct and relatively automated measurement of this vascular density.
Measures of oral mucosal vascular density (OMVD)—the density of visible blood vessels in the lower lip—were significantly higher in 33 FAP patients than in 50 healthy controls, according to investigator Francis Giardiello, MD, director of the Johns Hopkins Hereditary Colorectal Cancer Program, part of the Johns Hopkins Kimmel Cancer Center in Baltimore, Maryland. “About 90% of controls were below that threshold, so in principle, we could use that threshold for screening purposes,” observed Giardiello in a statement describing his group's findings, which were published in Familial Cancer (2011;10:309-313).
An additional five patients with multiple adenomas but no detectable mutation for FAP or HNPCC on genetic tests underwent the OMVD test, ultimately scoring above the high-risk threshold. “The results suggest that this high-OMVD condition may be an alternative marker for colon cancer risk, even when we can't find a gene mutation,” Giardiello explained.