TUESDAY, May 15, 2007 (HealthDay News) -- Researchers say genetic markers on seven different chromosomes can help predict how aggressive a breast tumor is likely to be.
Importantly, the markers were located in the stroma (the tissue surrounding the tumor cells), indicating that this might be a new target for therapy and for prevention.
The same markers have already been implicated in two other cancers.
"Like any good study, this needs to be replicated," said Dr. Charis Eng, senior author of the study and chairman of the Genomic Medicine Institute at the Cleveland Clinic in Ohio. "But, the fact that it has happened three times in different solid tumors says that it's important. Since these things are in the stroma and are associated with good surrogates of outcome (lymph node metastases and cancer grade), these would be excellent new prognostic indicators," she said.
"It also says that we should not just be targeting the whole cancer but thinking very seriously about targeting therapies and even preventive measures to the stroma," Eng added.
The study is published in the May 16 issue of the Journal of the American Medical Association.
Sporadic breast cancers, or breast tumors that are not inherited, often behave very differently from each other, making it difficult to determine the best treatment for a particular patient.
In the age of personalized medicine, research is just now turning to the stroma to help explain these differences.
"The role of the stroma is going to be very important in understanding the behavior of a variety of tumors, and this is a beginning look," explained Dr. Arthur Frankel, professor of internal medicine at Texas A&M Health Science Center College of Medicine and director of both the Cancer Research Institute and of the Division of Hematology/Oncology at Scott & White, in Temple.
"In the old days, people thought -- and many people still think -- that a cancer is uniform," Eng added. "We know that's not true. Our bodies are made up of regions and layers. Previous studies just looked at the carcinoma or looked at everything mashed together."
Here, the researchers analyzed DNA from the epithelium (membrane tissue) and stroma of 220 breast cancer tumors.
They found eight genetic markers on seven chromosomes within the stroma that were associated with differences in features of the tumors, including the grade of the cancer and how likely it was to have spread to the lymph nodes.
By contrast, only one chromosomal region in the epithelium had any similar associations.
Getting these findings into doctors' offices to help patients is a long way off, however.
"The next step is to replicate the findings in an independent series," Eng said.
For more information on breast cancer, visit the American Cancer Society.