Loss of PTEN Expression in Pancreatic Ductal Adenocarcinoma Is Associated with Poor Survival
Wai Chin Foo, Asif Rashid, Hua Wang, Stanley Hamilton, Mathew H Katz, Jeffrey E Lee, Henry F Gomez, James L Abbruzzese, Jason B Fleming, Huamin Wang. University of Texas, M.D. Anderson Cancer Center, Houston, TX
Background: 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.
Design: A tissue microarray was constructed from 133 surgically resected stage II pancreatic ductal adenocarcinomas (PDA). The microarray included 78 males and 57 females with a median age of 64 (range, 25 - 85). PTEN expression was evaluated by immunohistochemistry (IHC). The IHC slides were evaluated independently by two pathologists. The IHC results were categorized into PTEN-negative (no staining or staining in <5% of the tumor) and PTEN-positive (positive staining in ≥5% of the tumor cells). The staining results were correlated with clinicopathologic features and survival.
Results: Thirty-four of 133 (25.6%) cases were PTEN-negative. Recurrence/metastasis was observed in 88% (30/34) of patients whose tumors were PTEN-negative compared to 69% (68/99) in patients whose tumor were PTEN-positive (p=0.03). Patients whose tumors were PTEN-negative had shorter overall survival (median: 19.9±3.6 months) than those whose tumors were PTEN-positive (32.7±5.0 months, p = 0.03). In multivariate analysis, loss of PTEN expression was an independent prognostic factor for poor overall survival in patients with stage II PDA. No significant correlations between PTEN expression and other clinicopathologic parameters were observed.
Conclusions: Loss of PTEN expression is associated with poor survival in patients with stage II PDA. Assessment of PTEN expression may be used as a prognostic marker for patients with resected PDA.
Tuesday, March 20, 2012 1:00 PM
Poster Session IV # 282, Tuesday Afternoon