Genes Discovered That May Predict Breast Cancer Spread to Lungs
Finding could one day help doctors better tailor therapy for patients, study says
WEDNESDAY, July 27, 2005 (HealthDay News) -- Researchers have identified a set of genes that seems to predict if breast cancer will spread to the lungs and how serious the disease will be.
The finding could eventually help doctors to predict whose disease will become aggressive and spread, and potentially help them to better target treatments. The lungs and the bones are frequent sites for cancer that spreads from the breast. And cancer that spreads from the breast to organs such as the lungs accounts for the majority of breast cancer-related deaths, research has shown.
"We are the first to identify a clinically relevant set of genes that can predict metastases [spread] of breast cancer to the lungs," said study co-author Gaorav Gupta, a graduate student and researcher at Memorial Sloan-Kettering Cancer Center in New York City.
A report on the finding appears in the July 28 issue of Nature.
The researchers began with a set of cancer cell lines from 82 human breast cancer tumors. "We used a mouse model to mimic metastases," Gupta said. "We take these cells and inject them into a special type of mouse that allows you to inject human cells into them. We allowed lung metastases to form. We took out the lung metastases and took the cells and asked, 'What is special about these cells that will allow them to create the metastases?' "
To answer the question, the researchers used a "microarray" technique that allowed them to look at 22,000 genes all at once. Then they identified the genes that created the cancer spread to the lungs, and then put the genes back into the original cells to verify they were responsible.
Then they took another look at the human tumors. "We asked, of these 82 tumors, which ones expressed our genes [identified as those responsible for the spread]. We found a subgroup that expressed the genes and these patients were much more likely to develop lung metastasis."
Next, said Gupta, the research team hopes to repeat the findings in a larger group of patients, "to be certain this isn't just something unique about the cohort we selected."
If patients with these genes can be identified, the next avenue of research would be to figure out if there are specific drugs that could prevent the lung tumors from forming. Certain "inhibitor" drugs have already been shown to suppress the genes identified in the new study, Gupta said.
William C. Phelps, scientific program director of the research department for the American Cancer Society, praised the new study, saying, "Being able to identify a patient with a higher probability of developing metastasis would be of tremendous importance in terms of managing these patients."
The severity and course of cancer, even the same type, can be very different from patient to patient, Phelps said. "One of the decisions to struggle with is what [treatment] to give to which patients," he said. "Obviously, if you know cells in a particular tumor will be more likely to spread to the lung or bone, you would treat these patients more aggressively."
The identification of the gene pattern is a first step, he said. "If we can identify those genes, the next step may be to target the genes for therapy to prevent the spread of the tumors."
To learn more about breast cancer, visit the American Cancer Society.