New Hope for Breast, Prostate Cancer Testing
'Markers' in blood, tissue might help determine best treatment for each patient, studies suggest
The doctors found that the amount of Vav2 in pure DCIS is as low as in normal breast tissue, but that presence of the protein gradually increased in DCIS with micro-invasive cancer. The highest levels of Vav2 were found in DCIS with invasive cancer.
"Those lesions are twice as likely to have associated invasive breast cancer as lesions with low expression of Vav2," Guvakova said.
Statistical analysis revealed that the ability of Vav2 to predict progressive cancer in DCIS was 0.71. A value of 1 means the marker has a perfect discriminating power, and a value of 0.5 means that the marker's discriminating power is no better than chance.
"It is, in statistical terms, considered a very good predictor," Guvakova said. "It's definitely not by chance."
Their findings have not been published, but once that is accomplished the team will begin designing a study that would attempt to predict the behavior of DCIS in current patients, she said.
The Johns Hopkins research into prostate cancer focused on telomeres, which are sequences of genetic material located at the ends of chromosomes, that protect them. They function in much the same way that the plastic tips at the ends of a shoelace protect the lace from unraveling.
Doctors examined the DNA in immune cells drawn from blood samples provided by 441 men who later developed prostate cancer, as well as 421 men who did not develop prostate cancer.
The researchers found that among the men who developed prostate cancer, those with the shortest telomeres in their immune cell chromosomes were more than twice as likely to have developed aggressive prostate cancer compared to those men who had the longest telomeres.
Smoking appears to play a strong role. When the researchers narrowed their analysis down to current or former smokers, they found that those with the shortest telomeres in their immune cells were more than four times as likely to have developed aggressive prostate cancer.
"We don't yet know why having short telomeres in blood leukocytes [white blood cells] seems to be associated with risk of aggressive prostate cancer," researcher Elizabeth Platz, a professor in the department of epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore, said in a conference news release.
"It may tell us about a person's exposure to factors that increase their risk of prostate cancer, or it may be an indication of an inherent inability to maintain telomere length, which could put them at increased risk for this disease," Platz said. "If so, it might be that measuring telomere length in blood leukocytes could even predict risk of many different forms of cancer."
Because the studies were presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.