Discoveries
Study underscores the unknowns of research into inherited cancer risk
Sapna Syngal, M.D., M.P.H.
The first analyses of the human genome, completed in February, may make it seem that scientists are on the brink of linking specific genetic defects with certain kinds of inherited cancers. A recent study by Dana-Farber researchers suggests it won't be nearly that simple.
The study, led by Sapna Syngal,M.D., M.P.H., and Judy Garber,M.D., M.P.H., involved 250 Ashkenazi Jews who had a history of colon polyps, small buds of cells that can develop into cancer. Ashkenazi Jews were studied because a specific alteration in a gene called APC that has been linked to colon cancer has been found in 6 percent of that population.
The researchers made two discoveries, one that may have been expected and one that perhaps came as a surprise.
The first was that the patients — all of whom had had colon polyps — were more likely to carry the mutation than were Ashkenazi Jews who hadn't had polyps. Being born with the mutation, in fact, was found to double the risk of polyps.
Judy Garber, M.D., M.P.H.
The second finding was that carrying or not carrying the mutation made no difference in either the number or type of polyps that patients had, or the age at which they developed them. It might have been expected the mutation carriers would develop their polyps earlier in life, or have none of them.
The findings point the way to other genetic discoveries that may become commonplace in the years ahead. "With the completion of the Human Genome Project, scientists are going to find some mutations that have a strong influence over the types of diseases that people develop," Syngal says. "But they're also going to find mutations like the one we focused on that increase disease risk in subtle, complicated ways."
This was reported in the Aug. 10, 2000, issue of The Journal of the American Medical Association.
