Rb2 gene may play role in determining effectiveness of drug therapies.

2003 JUL 3 - (NewsRx.com & NewsRx.net) -- The tumor-suppressing gene pRb2/p130 may play a significant role in determining the effectiveness of drug therapies against breast cancer in women, according to a study by researchers at Temple University's Sbarro Institute for Cancer Research and Molecular Medicine.

The study was presented at an international scientific lecture on June 5, 2003, by Antonio Giordano, MD, PhD, director of the Sbarro Institute. It also was published in the June 5, 2003, issue of Oncogene.

In the study, led by Giordano, researchers at the Sbarro Institute looked at the estrogen receptor gene alpha, which plays a crucial role in normal breast development in women and has been linked to the development and progression of mammary carcinoma, or breast cancer.

The researchers found that in estrogen receptor-positive and estrogen receptor-negative mammary cell lines of women who have been affected with breast cancer, pRb2/p130 binds with the estrogen receptor gene alpha and sends out signals to engage or recruit a number of molecules.

"These key molecules together are recruited by pRb2/p130 onto the receptor gene alpha, which when expressed on mammary cell lines makes the breast tumors more responsive to treatment," says Giordano, who discovered the Rb2 gene while working at Temple's Fels Cancer Institute in the early 1990s.

The researchers discovered that in estrogen receptor-negative cell lines, pRb2/p130's signal is damaged or mutated and it recruits a different sequence of molecules that cause Rb2 to silence the expression of the estrogen receptor and block drug therapies from being successful against the cancer cells.

"There is a lack of success in therapies because the drug does not recognize the tumor cells anymore," says Giordano. "It cannot distinguish between the good cells and the bad cells.