The PTEN/PI3k/Akt pathway is a pathway in intracellular growth signal transduction that also plays an important role in the onset and progress of cancer. PTEN is a tumor suppressor that inhibits this pathway. This study examined how PTEN expression influences the prognosis of stage Ⅳ prostate cancer. Case subjects were extracted from The Queen s Medical Center cancer tumor registry database in Hawaii, USA, and included 192 stage Ⅳ prostate cancer patients that underwent androgen deprivation

more »

... apy (ADT) and who had a prostate tissue sample taken between 1992 and 2006. Of these, 133 cases under the age of 85 years whose tissue was available and could be assessed, and who did not receive anti-cancer chemotherapy, were extracted. We were able to obtain pretreatment PSA values in 108 of the 133 cases. Samples were immunohistochemically stained for PTEN and evaluated on a 4 level scale of 0, 1+, 2+, and 3+. The relationship between the overall survival rate and age/pretreatment PSA value/Gleason score, and the relationship between PTEN expression and overall survival rate were statistically analyzed. The age at ADT initiation, pretreatment PSA value, and median survival period was 71.2 years, 53.4 ng/ml, and 80.4 months, respectively. A Gleason score of less than 7 accounted for 25% and 75% had a score of over 8. The ratio of PTEN 0, 1+, 2+, and 3+ was 45%, 8%, 5%, and 42%, respectively. A correlation was found between pretreatment PSA values, Gleason score, and age in all stage Ⅳ prostate cancer cases, but there was no correlation with PTEN expression. On subdividing the 133 stage Ⅳ prostate cancer cases into the 3 stages of C, D1, D2 of the Jewett staging system, a correlation was found between PTEN expression and the survival rate in the stage D2 group. Moreover, in stage D2 prostate cancer, a significant difference between the Gleason score and PTEN expression was observed by multivariate analysis. This suggests that strong PTEN expression may be a prognostic factor of stage D2 prostate cancer and that such an expression is an independent prognostic factor.