Detection of a protein called p53 using a specific antibody test may be an improved biomarker for predicting worse survival in African-American women with breast cancer, according to a study at the University of Illinois at Chicago.
The study revealed that compared to Basal Subtype, a well known marker of poor prognosis for breast cancer, only p53 status was able to independently predict significantly worse survival for African-American women.
African American women have lower breast cancer incidence rates compared to White women, but suffer survival disparity with the highest mortality rates. They more commonly present with regional or distant disease, and have decreased survival for all stages. Survival disparity for African-American women may in part be due to more biologically aggressive tumors.
"The tumor suppressor gene p53 and Basal Subtype (regarded as tumors with negative estrogen receptor, progesterone receptor and human epidermal growth factor receptor-2 status) have both been of interest as markers of survival disparity, however this is the first study to directly compare p53 and Basal Subtype" said first author Keith A. Dookeran, MD, from the Department of Surgical Oncology at UIC.
Results were presented at the first meeting on Molecular Diagnostics in Cancer Therapeutic Development, organized by the American Association for Cancer Research.
Working with breast cancer tumor samples from 182 African-American women, Dr. Dookeran and his colleagues from the NCI-funded Minority-Based Community Clinical Oncology Program at Stroger Hospital in Chicago, used antibody Pab 1801 to detect abnormal accumulation of p53 protein on formalin-fixed, paraffin-embedded tissue.
"The advantage of this test is that it is relatively inexpensive and easy to perform on available tumor specimens with comparative results to more sophisticated techniques such as PCR" said Dookeran.
While p53 and Basal Subtype status were correlated, and both were able to predict mortality individually, after taking into account the effects of age and stage, only abnormal p53 expression was significantly correlated with poorer survival.
These results indicate that p53 is more likely than basal subtype to predict mortality in African-America women with breast cancer, and suggests that p53 is a better marker of survival disparity. The researchers note that the role of p53 as a new potential biomarker of poor prognosis for African-American women should be validated in larger studies.