New Hope for Breast, Prostate Cancer Testing
'Markers' in blood, tissue might help determine best treatment for each patient, studies suggest
The Pennsylvania researchers examined 211 remnants of tissue samples that had been taken to diagnose breast cancer. Of the samples, 42 were normal breast tissue, 71 were DCIS and 98 were invasive breast cancers.
DCIS involves the presence of abnormal cells inside a milk duct in the breast. In "pure" DCIS, the cells have not become cancerous and started to spread, said senior research investigator Marina Guvakova, an adjunct assistant professor in the department of surgery at the University of Pennsylvania.
However, there also are forms of DCIS that involve either fully invasive cancer or micro-invasive cancer, in which fewer than 10 percent of the abnormal cells have spread beyond the original tumor.
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.