Tau Protein Expression in Recurrent and Non-Recurrent Prostatic Adenocarcinoma
MP Gailey, G Lee, BR De Young. University of Iowa Hospitals and Clinics, Carver College of Medicine, Iowa City, IA
Background: Tau is a microtubule-associated protein whose principle function is in stabilizing and promoting microtubule (MT) assembly. Previous studies have investigated the relationship between tau protein expression and drug resistance in certain forms of carcinoma. These studies suggest that tau protein competes with antimotitic drugs for binding sites on MTs and thus renders resistance. However, another study has shown that in prostatic adenocarcinoma tau does not bind MTs, suggesting another mechanism of resistance. No studies to date that have examined the relationship of tau protein expression and outcome in prostatic adenocarcinoma.
Design: We matched 26 patients with recurrent prostatic adenocarcinoma and 25 patients, who were free of recurrent prostatic adenocarcinoma after 10 years of follow-up, according to Gleason score and margin status at prostatectomy. Utilizing standard technique, immunohistochemical staining of formalin fixed paraffin embedded tissue from each patient's prostatectomy specimen was performed with an antibody specific for tau-13 (B11E8, 1:12,500 dilution). Tau protein expression was recorded as the percentage of tumor cells that stained positive.
Results: In patients with recurrent prostatic adenocarcinoma, a slightly higher percentage of tumor cells (52%) showed tau expression when compared to those without recurrence (46%). However, no statistical difference between cases of recurrent versus non-recurrent prostatic adenocarcinoma was identified (p=0.61). Moreover, expression of tau was variable, independent of Gleason score at prostatectomy (R2=0.02 and 0.003 for non-current and recurrent cases, respectively). Tau expression also varied within the same gland amongst benign acini, acini involved with high grade prostatic intraepithelial neoplasia and adenocarcinoma.
Conclusions: These findings demonstrate that while cases of recurrent prostatic adenocarcinoma show slightly higher expression of tau protein expression, no statistical difference in expression was identified. Furthermore, Gleason score does not correlate with tau expression and there is variable staining for tau between both benign and malignant acini within the same gland. These results support the hypothesis that tau is a multi-functional protein that does not influence outcome prostatic adenocarcinoma.
Category: Genitourinary (including renal tumors)
Wednesday, March 24, 2010 9:30 AM
Poster Session V # 99, Wednesday Morning