April 7, 2009

Genetic Pair Important in Breast Cancer

Scientists know a protein gene called PTEN is a major tumor-suppressor. When it's reduced or mutated, cancers can grow.

Researchers from the University of Texas M.D. Anderson Cancer Center have discovered a second gene that appears to protect PTEN, a finding that could one day lead to new treatments for cancers of the breast and other organs.

The new gene is called Rak, and it works to stabilize PTEN by attaching a phosphate group to the protein, thus blocking an enzyme that leads to its destruction.

The investigators confirmed their laboratory findings by injecting mice with cells that over-express Rak. Those mice did not develop breast cancer. When mice were injected with cells with compromised Rak, all of them developed tumors.

"We've clearly discovered the missing link that explains how Rak can stabilize PTEN protein to prevent breast cancer development," study author Shiaw-Yih Lin, Ph.D., was quoted as saying. "Our research explains why PTEN is defective in breast cancer and provides important clues for the development of effective therapy in Rak- or PTEN-defective breast cancers."

Since PTEN is often mutated or inactivated in other cancers too, such as melanoma and those of the prostate and endometrium, these findings have implications for those diseases as well.

SOURCE: Cancer Cell, published online April 6, 2009