Expression of p27, B-Catenin and TIMP-3 in Prostatic Tissues of African-American Men

Marvin E, Myles, Qiangwei Ma, Rodney Davis, Ben Shenassa, Oliver Sartor, Carmen Espinoza, Syeda Sarwar, George Karabatsos, and Walter Rayford

Objectives: Prostate cancer (Pca) occurs at a higher incidence and is more aggressive in African American men than in Caucasian men in the U.S. The purpose of this study was to identify prognostic markers that may be differentially expressed in prostatic cancer between African-American and Caucasian American men. We examined p27 (Kip1) (p27), B-catenin, and TIMP-3 expression.

Results: The mean Gleason score for the African American men was 7.3 and that for the Caucasian men was 6.6 (p>0.5). The mean preoperative PSA values were 9.8 ng/cc and 12.1 ng/cc for Caucasians and African Americans, respectively (p>0.5). Of 88 patients, 85 (96.6%) had some degree of p27 expression. For Caucasians, there was an even distribution between low and high expression categories. For African Americans, the percentages were approximately 40% and 60% for low and high expression respectively. B-catenin gave uniform and high expression (75% to 100% positive staining) for both groups, but 26.7% of African American PCa patients showed undetectable levels of TIP-3 immunostaining, which is statistically significant (p>0.5).

Conclusion:  African-American PCa patients are 1.5 times more likely to have high levels of p27 protein than Caucasian PCa patients. There was not a statistically significant difference in the immuno-histochemical expression of biochemical markers we evaluated between African-Americans and Caucasian American men with prostate cancer. It is important to evaluate whether other markers can contribute to the apparent pathophysiological differences in prostate cancer progression among these groups.