(RxWiki News) To determine treatment for prostate cancer, doctors may look to a patient’s DNA. How aggressive the disease will be may be predicted by examining gene patterns in blood cells.
Through blood tests from cancer patients, scientists have discovered distinct genetic “signatures.”
These can help identify which patients have more life-threatening, fast-growing tumors that need to be treated immediately.
"Ask your doctor how blood tests work."
William Oh, MD, chief of the Division of Hematology and Medical Oncology of The Tisch Cancer Institute at The Mount Sinai Medical Center in New York City, and his research team examined blood from 202 men with treatment-resistant prostate cancer.
Along with fellow scientists from Dana-Farber Cancer Institute in Boston and Memorial Sloan-Kettering Cancer Center in New York City, Dr. Oh pinpointed six genes that are characteristic of a treatment-resistant form of the disease.
A particular pattern or group of genes in a cell is called a signature and is characteristic of certain conditions.
Men with the six-gene signature were considered high risk, and expected to live 7.8 months. Men who didn’t have this signature were considered low risk and lived about 35 months.
A follow-up study of 140 men validated the findings.
Many prostate cancers can spread quickly but often they are not life threatening. According to the American Cancer Society, more than 2.5 million men in the United States who have been diagnosed with prostate cancer are still alive.
While there are tests for aggressive forms of prostate cancer, they are not always accurate.
In a similar study to Dr. Oh’s, British investigators also found genetic signatures in blood samples that indicate aggressive forms of prostate cancer.
Dr. Johann de Bono, who led research at Britain's Institute of Cancer Research, said in a statement, “Our test reads the pattern of genetic activity like a barcode, picking up signs that a patient is likely to have a more aggressive cancer. Doctors should then be able to adjust the treatment they give accordingly.”
Dr. de Bono and his colleagues examined blood samples from 100 patients with prostate cancer. In a group in which patients died significantly earlier than others, scientists identified nine key active genes shared by all those patients.
Both scientists from the United States and Britain said the gene signature they found included several genes involved with the immune system.
They suggest that the immune system is suppressed in patients whose cancers spread throughout the body.
“There is an urgent need for predictive models that help assess how aggressive the disease is in prostate cancer patients, as survival can vary greatly," said Dr. Oh. "Our six-gene model, delivered in a simple blood test, will allow clinicians to better determine the course of action for their patients, determine clinical trial eligibility, and lead to more targeted studies in late-stage disease."
Both studies were published in October in the journal The Lancet Oncology.