Loss of phosphatase and tensin homolog expression is associated with recurrence and poor prognosis in patients with pancreatic ductal adenocarcinoma

Abstract

Phosphatase and tensin homolog (PTEN) is a tumor suppressor in the AKT/mTOR pathway. Animal model studies have shown that loss of PTEN function is involved in the progression of pancreatic cancer. However, the prognostic significance of loss of PTEN expression in pancreatic cancer is unclear. PTEN expression was evaluated by immunohistochemistry on tissue microarrays consisting of multiple cores of 133 resected stage II pancreatic ductal adenocarcinomas. A PTEN expression score was calculated as the product of the percentage of positive tumor cells and the intensity of PTEN staining. We categorized PTEN expression for each tumor as retained (PTEN score >5) or lost (PTEN score ≤5). Thirty-four (25.6%) patients had tumors with loss of PTEN expression, and 99 (74.4%) had tumors with retained PTEN expression. Recurrence/Metastasis was observed in 88.2% (30/34) of patients whose tumors showed loss of PTEN compared with 68.7% (68/99) of patients whose tumors showed retained PTEN (P = .03). Patients whose tumors showed loss of PTEN had a shorter overall survival (median, 19.9 ± 3.6 months) than did patients whose tumors had retained PTEN (32.7 ± 5.0 months, P = .03). In a multivariate analysis, loss of PTEN expression was an independent prognostic factor for poor overall survival in patients with stage II pancreatic ductal adenocarcinoma. No significant correlations between loss of PTEN expression and other clinicopathologic parameters were observed (P > .05). Assessment of PTEN expression may be used as a prognostic marker for patients with resected pancreatic ductal adenocarcinoma.