PTEN (phosphatase and
tensin homolog on chromosome 10) is one of the most frequently lost tumor suppressor genes in human
cancers and it has been described in more than two-thirds of patients with advanced/aggressive
prostate cancer. Previous studies suggest that, in
prostate cancer, genomic PTEN loss is associated with
tumor progression and poor prognosis. Thus, we evaluated whether immunohistochemical PTEN expression in
prostate cancer glands was associated with higher risk of recurrence, using a nested case-control study that included 451 men who recurred and 451 men who did not recur with clinically localized
prostate cancer treated by radical
prostatectomy. Recurrence was defined as biochemical recurrence (serum
prostate-specific antigen >0.2 ng/ml) or clinical recurrence (local recurrence, systemic
metastases, or
prostate cancer-related death). Cases and controls were matched on pathological T stage, Gleason score, race/ethnicity, and age at surgery. Odds ratios of recurrence and 95% confidence intervals were estimated using conditional logistic regression to account for the matching factors and to adjust for year of surgery, preoperative
prostate-specific antigen concentrations, and status of
surgical margins. Men who recurred had a higher proportion of PTEN negative expression (16 vs 11%, P=0.05) and PTEN loss (40 vs 31%, P=0.02) than controls. Men with markedly decreased PTEN staining had a higher risk of recurrence (odds ratio=1.67; 95% confidence intervals 1.09, 2.57; P=0.02) when compared with all other men. In summary, in patients with clinically localized
prostate cancer treated by
prostatectomy, decreased PTEN expression was associated with an increased risk of recurrence, independent of known clinicopathological factors.