CAMBRIDGE, Mass. (August 13, 2007) In some ways, certain tumors resemble bee colonies, says pathologist Tan Ince. Each cancer cell in the tumor plays a specific role, and just a fraction of the cells serve as queens, possessing the unique ability to maintain themselves in an unspecialized state and seed new tumors. These cells can also divide and produce the worker cells that form the bulk of the tumor.
These queens are cancer stem cells. Now the lab of Whitehead Member Robert Weinberg has created such cells in a Petri dish by isolating and transforming a particular population of cells from human breast tissue. After being injected with just 100 of these transformed cells, mice developed tumors that metastasized (spread to distant tissues).
The operational definition of a cancer stem cell is the ability to initiate a tumor, so these are cancer stem cells, declares Weinberg, who is also an MIT professor of biology.
Ince didnt set out to engineer these potent cells. As a post-doctoral researcher in the Weinberg lab and gynecologic pathologist at Brigham and Womens Hospital, he was simply trying to create breast cancer models that look like real human tumors under the microscope and behave like those seen in many patients.
In more than 90 percent of human breast tumors, cancer cells resemble those lining our bodys cavities. A trained pathologist can spot the similarities under a microscope. But the cancer cells previously engineered from normal breast cells for laboratory studies looked different. Ince suspected that researchers were transforming the wrong type of cells.
Now an independent investigator at Brigham and Womens Hospital and an instructor at Harvard Medical School, Ince developed a recipe for a new chemically defined culture medium and managed to grow a different type of human breast cell that ordinarily dies in culture. He transformed it into a cancer cell by inserting specific genes through a standard
Contact: Alyssa Kneller
Whitehead Institute for Biomedical Research