Two Types of Cancer Stem Cells?

In addition to the cancer stem cells found in breast tumors, Boston researchers have found a second causative cell they say is critical.

If the breast cancer cells were all coming from a single cancer stem cell, you might be able to cure the disease with just one drug, said Kornelia Polyak, who led the research. Our findings suggest that the tumor cells come from a ‘stem-like’ progenitor cell and then diverge genetically, so I think you have to treat both cell types.

The theory up until now has been that normal cells mutate into cancer cells, which also mutate and create a genetically varied tumor.

The stem-cell theory says that a single, abnormal adult stem cell can multiply into a population of genetically identical tumor cells. Polyak and her colleagues at Dana-Farber Cancer Institute, Harvard Medical School, Johns Hopkins and the Vavilov Institute for General Genetics in Moscow have added to that theory, saying that in addition to abnormal adult stem cells, the progenitor cells must be addressed.

When the team analyzed the new cells genetically, they discovered that they were driven by a molecular mechanism called the TGF-Beta1 signaling pathway that could be blocked by experimental drugs now entering clinical trials.

The research was published in the March issue of Cancer Cell.