OBJECTIVES: Microsatellite instability has been found in a variety of tumors including prostate cancer. Bax, a pro-apoptotic protein from the Bcl-2 family of proteins, has a microsatellite composed of an eight deoxyguanine [(G)8] tract located in exon 3. Prostate carcinoma cells have increased proliferation indices and lower levels of apoptosis when compared to benign tissue. We investigated whether instability in the Bax (G)8 microsatellite contributes to loss of apoptotic control in localized prostate cancer.
PATIENTS AND METHODS: Thirty-eight patients undergoing radical prostatectomy for localized prostate carcinoma participated in this study. Prostate carcinoma was microdissected, and polymerase chain reaction amplification of a region containing the (G)8 microsatellite was performed on DNA from peripheral blood leukocytes and tumors, followed by single strand conformational polymorphism (SSCP) analysis and direct DNA sequencing.
RESULTS: SSCP analysis showed no alteration in the number of bands detected upon comparison of tumor tissue to leukocytes, suggesting no alterations in the microsatellite. This was confirmed by direct sequencing, which demonstrated a normal (G)8 sequence in each case.
CONCLUSION: We conclude that the Bax (G)8 microsatellite is stable in localized stage T2 and T3 prostate cancer. Our findings argue against a mutator phenotype pathway leading to loss of apoptotic control in localized prostate cancer.