Johns Hopkins researchers, collaborating with an international team of geneticists, have pinpointed the site of the first gene for a major cancer located on the human X chromosome. The gene, for prostate cancer, may account for almost 20 percent of disease in families with a strong history of the cancer, the researchers say. It's the second prostate cancer susceptibility gene this group has mapped, and the first on the X chromosome, which men inherit from their mothers.
"This is clearly a major step toward understanding the factors that lead to prostate cancer," says Hopkins Urologist-in-Chief, Patrick C. Walsh, M.D., one of the study's authors. "We're still at the early stages in figuring out genetic involvement in prostate cancer, but this finding is real progress," says Hopkins geneticist, William Isaacs, Ph.D., a co-director of the study.
The research, reported in the October Nature Genetics, describes the new gene locus, called HPCX (for human prostate cancer on the X chromosome) as responsible for 15 to 20 percent of inherited forms of the diseases. Of the approximately 200,000 new cases diagnosed in the U.S. each year, an estimated 10 percent are inherited.
The study confirms researchers' long-held suspicion that the X chromosome might be important in prostate cancer. Since the 1960s, they have noted that a man's risk of prostate cancer tends to be higher if his brother has prostate cancer than if his father has the disease. That inheritance pattern characterizes genetic traits carried on the X chromosome and passed from mothers to sons, such as muscular dystrophy or hemophilia. The plausible explanation is that a prostate cancer susceptibility gene lies on the X chromosome.
"Mapping HPCX brings us one step closer to understanding the origins of
prostate cancer, at least in some families," says Francis Collins, M.D.,
director of the National Human Genome Research Institute and an author from
Contact: Gary Stephenson
Johns Hopkins Medical Institutions