News Release

Other highlights in the August 7 issue of JNCI

Peer-Reviewed Publication

Journal of the National Cancer Institute

Matrix metalloproteinase in nontumor cells may contribute to growth of ovarian tumors
Increased expression of matrix metalloproteinase-9 (MMP-9) has been associated with metastasis and invasion of human ovarian cancer cells. This enzyme is also expressed in the underlying stromal (nontumor) cells.

In the August 7 issue of the Journal of the National Cancer Institute, Isaiah J. Fidler, D.V.M., Ph.D., and his colleagues at the University of Texas M. D. Anderson Cancer Center in Houston found that stromal MMP-9 expression contributes to angiogenesis and the progression of human ovarian tumors in mice.

The researchers injected human ovarian cancer cells into the peritoneal cavities of mice that expressed MMP-9 and mice genetically engineered to lack the gene. They then examined tumor incidence, tumor size, blood vessel density, and macrophage infiltration. In mice expressing MMP-9, the human ovarian tumor cells produced rapidly growing tumors with a dense network of blood vessels. In contrast, fewer tumors and blood vessels formed in mice lacking the MMP-9 gene.

"Targeting expression of MMP-9 in tumor cells, and more so in nontumor cells, may therefore be an effective approach to control angiogenesis and carcinomatosis of human ovarian tumors," the authors conclude.

Contact: Julie Penne, M. D. Anderson Cancer Center, (713) 792-0655, jpenne@mail.mdanderson.org

Dense breasts and past mammograms may compromise diagnostic mammography
Dense breasts and past mammography appear to compromise the performance of diagnostic mammography among women with signs or symptoms of breast cancer, according to a study appearing in the August 7 issue of the Journal of the National Cancer Institute.

Diagnostic mammography is used to identify breast cancers in women who have shown signs or symptoms of the disease, but the sensitivity and specificity of the technique remains unclear. Researchers have suggested that the performance of the technique could be altered by age, breast density, past mammographies, and presence of breast cancer symptoms.

To determine whether these factors influence the performance of diagnostic mammography, William E. Barlow, Ph.D., Group Health Cooperative in Seattle, Washington, and colleagues from the Breast Cancer Surveillance Consortium linked records from mammography registries to cancer outcomes in 1,340 cases of breast cancer diagnosed within 1 year of the mammogram. The authors considered various factors, including age, breast density, prior mammograms, and self-reported breast lumps.

The authors found that increasing breast density and previous mammography were associated with decreased sensitivity of diagnostic mammography. However, specificity, or the ability to rule out cancer, increased with a previous mammogram. In contrast, a self-reported breast lump was associated with increased sensitivity but decreased specificity.

"With increased prevalence of screening mammography, tumors detected by diagnostic mammography will be smaller and of an earlier stage," the authors write. "The sensitivity and specificity of diagnostic mammography may be reduced unless they are enhanced with further additional imaging, particularly for women with dense breasts."

Contact: Christie Price, Group Health Cooperative, (206) 533-1627, cprice@email.marketfitz.com

Equal access to health care may reduce racial differences in colon cancer survival rates
When access to health care and treatment is equal, African-American and Caucasian colorectal cancer patients appear to benefit similarly from adjuvant chemotherapy and disparities in survival all but disappear, according to a study in the August 7 issue of the Journal of the National Cancer Institute.

In this analysis of data from a randomized phase III study, A. David McCollum, M.D., and Charles S. Fuchs, M.D., of the Dana-Farber Cancer Institute and their colleagues compared survival outcomes and toxicity among 344 African-American and 3,036 Caucasian patients enrolled in a randomized phase III trial of adjuvant chemotherapy for stage II and stage III colon cancer. The patients had similar access to health care resources and treatment.

The researchers found no differences in disease-free survival or overall survival at five years between the African-American and Caucasian patients in the study. However, Caucasian patients experienced statistically significantly more diarrhea, nausea, vomiting, and stomatitis than African-Americans.

The authors note that their findings contrast with other studies that have found worse outcomes among African-Americans with colon cancer than Caucasians. They point out that by studying patients in a single large trial, they have limited biases introduced by differences in access to health care. Although they note that patients who participate in trials may differ from the population at large, their study population included patients from various medical centers across the United States and Canada. "We believe that our findings are representative of the general U.S. population," they conclude.

Contact: Janet Haley-Dubow, Dana-Farber Cancer Institute, (617) 632-5665, janet_haley@dfci.harvard.edu

Aspirin users may have lower risk of pancreatic cancer
Use of aspirin is associated with decreased incidence of pancreatic cancer, according to results from a large-scale prospective study published in the August 7 issue of the Journal of the National Cancer Institute.

Kristin E. Anderson, Ph.D., Aaron R. Folsom, M.D., and their colleagues at the University of Minnesota School of Public Health examined the use of aspirin and other non-steroidal anti-inflammatory drugs among 28,283 postmenopausal women from 1992 through 1999. Women who used any aspirin had a 43% lower risk of pancreatic cancer than nonusers. Increasing frequency of aspirin use was inversely associated with the risk of pancreatic cancer. However, use of nonaspirin NSAIDs was not associated with any changes in pancreatic cancer risk.

"If the associations observed here are causal, we estimate that 43% of pancreatic cancer cases among nonusers of aspirin might be prevented by aspirin use," the authors write. "Further studies of pancreatic cancer and NSAID use, with detailed assessments of dose, duration, and drug type used, are warranted."

Contact: Tonya Femal, University of Minnesota, (612) 625-2640, femal001@umn.edu

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