New Targets in Fight Against Breast Cancer

The Salk researchers found similarities in genetic activity of breast cancers and mammary stem cells found in developing mouse embryos (pictured here against a background of fat tissue). Their findings offer clues to developing personalized therapies for cancers. (Credit: Courtesy of Dannielle D. Engle)

Scientists Use Old Theory

In a paper published February 3 in Cell Stem Cell, the scientists report striking similarities between genetic signatures found in certain types of human breast cancer and those of stem cells in breast tissue in mouse embryos. These findings suggest that cancer cells subvert key genetic programs that guide immature cells to build organs during normal growth.

The Salk scientists first made the surprising finding that these fetal breast stem cells were not fully functional until just prior to birth. This observation suggested that a very special landscape is needed for a cell to become a stem cell. The breast stem cells at this late embryonic stage were sufficiently abundant to simplify their isolation. This enabled their genetic signature to be determined, and then compared to that of the stem-like cells in breast cancers.

The signatures of the breast stem cells in the fetus were stunningly similar to the stem-like cells found in aggressive breast cancers, including a significant fraction of a virulent cancer subtype known as “triple-negative.” This is important as this type of breast cancer has until now lacked the molecular targets useful for designing personalized therapeutic strategies.

“The cells that fuel the development of tumors in the adult are unlikely to ‘invent’ entirely new patterns of gene expression,” says Benjamin Spike. “Instead, some cancer cells seem to reactivate and corrupt programs that govern fetal tissue stem cell function, including programs from their neighboring cells that constitute the surrounding fetal stem cell landscape, or microenvironment.”

The discovery of the shared genetic signatures provides a new avenue for scientists to explore the links between development and cancer. By uncovering new biological markers, the scientists hope to develop tests that individualize treatment by showing how the GPS system of a tumor operates. This should help doctors to determine which patients may benefit from treatment, and the correct types of treatment to administer.

The research was sponsored by the Breast Cancer Research Foundation, the U.S. Department of Defense, the G. Harold & Leila Y. Mathers Foundation and Susan G. Komen for the Cure.  Read Full Story

 

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