Case Number 107055 - RB Functional Status as a Determinant for Breast Cancer Therapy

Contact: Lynn Briggs
Phone: 513-558-3098

Description:  Breast cancer is the second leading cause of cancer death in US women, after lung cancer. It is estimated that about 200,000 women in the United States will be diagnosed with invasive breast cancer in 2006 and that about 40,000 women will die from the disease.
In a recently published article in the Journal of Clinical Investigation, Dr. Erik Knudsen and colleagues at the University of Cincinnati discovered a link between inactivation of the retinoblastoma (RB) tumor suppressor and the response of cancer cells to anti-tumor therapies, including anti-estrogens and DNA damaging agents.
A gene expression signature of 59 genes that are deregulated with RB loss and repressed upon RB activation was used to group breast cancer patients. Patients showing high expression of RB regulated genes, indicating loss of RB function, had increased incidence of cancer recurrence relative to patients in the medium or low level expression groups. Thus, the loss of RB function in breast cancer tumors, as assessed by the expression of 59 signature genes, correlated with decreased effectiveness of tamoxifen monotherapy.