Identifying protein markers in the blood that indicate how ovarian cancer responds to therapy is one goal of a Medical College of Georgia pilot study.
"We want to identify new, more specific markers that will give gynecologic oncologists and their patients a better idea of how ovarian cancer is responding to treatment so they can change treatment if it's not working," said Dr. Daron G. Ferris, family medicine physician and director of the Gynecologic Cancer Prevention Center at MCG Medical Center.
"We also want to identify markers that can be used as an effective screening test for this disease which unfortunately is typically caught in its later stages. When the Georgia Cancer Coalition provided the opportunity for funding a pilot project to do this, we seized the opportunity," said Dr. Ferris, principal investigator on the study recently funded by the Georgia Cancer Coalition, a charitable organization formed in 2001 to improve cancer treatment in Georgia.
Ovarian cancer is among the top five cancers diagnosed in women, and although survival rates can be as high as 80 to 90 percent when caught early, most cancers are found after the disease has progressed, because it's asymptomatic early on and because there is no screening test, said Dr. Sharad Ghamande, gynecologic oncologist and a co-investigator on the new study. With today's standard treatment, surgery to remove the tumor followed by chemotherapy, survival rates for late-stage ovarian cancer are 30 to 35 percent.
Long-term, the researchers' quest for biomarkers may lead to better treatments by identifying specific proteins expressed by ovarian cancer that could be targets for drugs, such as monoclonal antibodies designed to help the body attack the cancer.
Researchers will take blood samples at various intervals as women with ovarian cancer proceed from diagnosis to treatment to remission to disease recurrence or continued remission then use advanced, high-throughput technology called proteomics to look at protein expression changes as well as differences between those who respond best to therapy and those whose cancer recurs.
"You don't have to look at every single protein; you only have to find one or two that are going to be useful of the tens of thousands or maybe millions of proteins that may be expressed by ovarian cancer," said Dr. Jin-Xiong She, director of the MCG Center for Biotechnology and Genomic Medicine and study co-investigator. "For the moment, we are trying to develop prognostic tests for ovarian cancer treatment. But of course, as the project progresses, we will try to understand why certain patients can be cured and others cannot."
"We have to better understand the disease process," said Dr. Eileen D. Dickman, clinical research scientist, coordinator of the Gynecologic Cancer Prevention Center and a study co-investigator. "If you can watch a biomarker over time that decreases as you get chemotherapy, you can think, wow, maybe this one is more associated with ovarian cancer. We are taking the same women at diagnosis and remission and looking at what's different. We should get an enriched pool of specific biomarkers and that's our strength. No one really has been able to take a lot of serum from the same patients."
The researchers will use the proteomics facility to also compare proteins expressed by different women with ovarian cancer and by healthy women without it to help identify the best biomarkers, Dr. She said.
CA 125 is one biomarker known to be expressed in about 90 percent of women with ovarian cancer; physicians measure its level in the blood when they suspect ovarian cancer and monitor its level throughout treatment, said Dr. Ghamande, who recently began a clinical trial of a monoclonal antibody that targets this biomarker.
But CA 125 is not unique to ovarian cancer and is expressed in many benign conditions such as endometriosis and fibroid tumors.
The MCG researchers believe their study will identify more specific markers. "Many women with this disease focus on their CA 125 levels and worry that a one point increase means their disease is getting worse and they will have to go through treatment again," Dr. Dickman said. "We want to give them better options."
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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