Differential PTEN protein expression profiles in superficial versus invasive bladder cancers.

INTRODUCTION The prognostic significance of PTEN protein loss in bladder cancer is not well established. The objective of this study was to investigate the PTEN expression profile in superficial noninvasive papillary transitional cell carcinoma (TCC) versus invasive TCC and compared the results with pathological and clinical parameters. MATERIALS AND METHODS Bladder tumor samples were obtained from 29 patients who underwent surgery for superficial (n=11) and invasive (n=18) bladder cancers at the Akdeniz University Hospital. The patient profile including sex, age, histological grade and the stage, presence of carcinoma in situ, cystoscopy findings (tumor size, location, multiplicity) were obtained by examining the patients' medical records. No patient received anticancer agents prior to the operation. Western blotting was performed using bladder carcinoma samples in order to determine the level of PTEN protein expression for each patient. RESULTS Only 4 (13.7%) patients with bladder carcinoma manifested a decrease in the level of PTEN expression. Regarding the correlation between tumor stage and the PTEN expression, with the exception of patient 23 all patients who displayed a reduction in PTEN expression had muscle-invasive TCC. CONCLUSION Future studies with a clinical follow-up will be needed to determine if those superficial tumors with decreased PTEN expression are going to progress to a later stage. Based on our results PTEN by itself does not seem to be a good candidate as an independent marker to predict the behavior of bladder cancers.