(Ivanhoe Newswire) – 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
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