Higher grade tumors are more likely to spread.
Prostate cancer patients who carry a certain genetic variant are at significantly higher risk for aggressive tumors, researchers say.
The finding could lead to a blood test to predict who is susceptible to aggressive malignancies. In addition, knowing which men carry this genetic marker may help better guide clinicians in how to treat the cancer.
Researchers looked at 551 men with prostate cancer (mean age at surgery was 60 years). Among these men, 28% had a first-degree relative with prostate cancer and a mean PSA level of 5 ng/mL. All except 31 subjects underwent a radical prostatectomy.
The genetic variant occurs on chromosome 8q24. Carriers of this variant had a 40% chance of having a close family member with prostate cancer compared with a 20% chance among men without the variant. Carriers also had cancers that were more likely to spread to the lymph nodes and more difficult to cure with surgery alone. They also tended to have higher Gleason scores, extracapsular extension, and seminal vesicle invasion.
“These findings will help us understand the mechanisms underlying prostate cancer,” said co-principal investigator Brian Helfand, MD, PhD, assistant research professor of urology at Northwestern University’s Feinberg School of Medicine in Chicago. “They hold great promise for the development of new treatments and prevention.”
This genetic marker is twice as common in African-American men, Dr. Helfand said. At least 30% of African-American men with prostate cancer carry the 8q24 variant compared with 15% of men of European descent.
The 8q24 genetic variant originally was discovered by deCODE Genetics, a biopharmaceutical company in Ice-land, in collaboration with William Catalona, MD, of Northwestern University, and two other research groups. Their findings were first reported in Nature Genetics in June 2006. Since then, the genetic variant has been widely duplicated by several genetic research groups around the world. This is the first time that a genetic mutation associated with prostate cancer has been found in such a large population of prostate cancer patients.
Dr. Helfand said he believes the 8q24 variants “hold many diagnostic possibilities.” He noted that studies identifying the 8q24 variants are among the first to demonstrate genetic alterations that contribute to the development of prostate cancer in a proportion of patients. “For years, people have looked for markers and if they found them they only accounted for a small percentage of prostate cancers,” he said.