Last Updated: 2008-06-26 16:24:49 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Stem cells can give rise to both breast cancer cells and the cells of the tumor microenvironment. Furthermore, stem cells transplanted from a donor can be the source of breast cancer in a transplant recipient.
"This is a whole new way of thinking about stem cells and cancer," Dr. Sanford H. Barsky told Reuters Health about research he is presenting at the Department of Defense's Era of Hope Breast Cancer Research meeting that has just convened in Baltimore, Maryland.
Dr. Barsky, of The Ohio State University in Columbus, and colleagues conducted two phases of study. One phase was a search of a bone marrow and organ transplant registry, in which "we noticed the origins of some cancers were from the donor organ," Dr. Barsky said. "Cancer-promoting donor stem cells lodged in different sites in the recipients and developed."
In the second phase of their research, conducted in mice, the Ohio team tagged bone marrow cells before transplantation. The researchers were able to observe that "breast cancer doesn't just arise in breast tissue and everything that contributes to the breast cancer microenvironment doesn't reside only in the breast."
"Invasive breast cancers reflect the presence of both cancer-promoting as well as cancer-initiating stem cells derived from ectopic locations," Dr. Barsky explained. "It appears that breast cancers and the tumors' microenvironment both arise from stem cells."
"Inflammatory breast cancers form from emboli in vascular channels, and these channels form the microenvironment. Both arise from donor stem cells and there is cross-talk between them," the researcher added.
In the abstract for their presentation, the investigators write, "These emboli, which were resistant to chemotherapy, exhibited a prominent stem cell-like phenotype...suggesting that the lymphovascular tumor emboli, like the human embryonal blastocyst, are derived from stem cells locked in self-renewal... some of the endothelial cells which lined the channels containing the tumor emboli exhibited evidence of bone marrow origin."
"This shows that we may be able to turn off cancer cells at the level of the stem cell," Dr. Barsky said. "If we can't stop the stem cells, then maybe we could replace the cancer cells with normal cells."
"Breast cancer is really a rare disease at the cellular level, despite the fact that it is fairly common on a population basis...and stem cells are rare in the breast," Dr. Barsky noted. "Our research could lead to a way of tagging cancer cells from their point of origin and may provide a new method of drug delivery."
http://www.oncolink.com/resources/article.cfm?c=3&s=8&ss=23&Year=2008&Month=06&id=15400
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