A group of researchers identified two proteins in the blood that could be used as prognostic markers for long-term survival in breast cancer patients. These proteins, C-reactive protein (CRP) and serum amyloid A (SAA), are associated with chronic inflammation, which is known to contribute to cancer development and progression.
The investigators measured CRP and SAA levels in 734 disease-free breast cancer survivors at 31 months after diagnosis. Patient data was drawn from the Health, Eating, Activity and Lifestyle (HEAL) study, a multiethnic prospective group of women diagnosed with stage 0 through stage 3a breast cancer.
“To our knowledge, this is the largest population-based cohort study to date that examined the relationship between systemic inflammation and breast cancer survival, and the first to evaluate SAA as a prognostic marker for breast cancer,” says Cornelia Ulrich, Ph.D., of the Fred Hutchinson Cancer Research Center.
They found that elevated levels of CRP and SAA are associated with reduced overall survival, regardless of patient age, tumor stage, race, and body mass index. Women with breast cancer who had SAA levels in the highest one-third segment were three times more likely to die from their disease within the following seven years compared to patients in the lowest-third segment. Similarly, women in the highest third of CRP levels had a twofold increased risk of death.
The team included scientists from Fred Hutchinson Cancer Research Center, University of Washington, NCI, City of Hope National Medical Center, University of Southern California, and the University of Louisville. Their findings appear in the May 18 edition of the Journal of Clinical Oncology.
CRP and SAA are nonspecific, acute-phase hepatic proteins that are secreted into the circulating bloodstream in response to cytokines including interleukin-1, interleukin-6, and tumor necrosis factor. In previous studies, elevated CRP was associated with poor survival in patients with metastatic prostate cancer as well as those with gastroesophogeal, colorectal, inoperable small-cell-lung, and pancreatic cancers.
Preoperative levels of SAA have been associated with survival of patients with gastric cancer and those with renal cell carcinoma. Data also suggests that chronic inflammation promotes mammary tumor development. Breast cancer patients have elevated concentrations of CRP before surgery, more so in women with advanced disease, which suggests that CRP may be related to tumor burden or progression.
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