Yonago Acta medica 2006;49:9-17
Expression of phospho-Akt and PTEN Proteins Predicts the Survival of Patients with Pancreatic Cancer
Yoshimi Ozaki-Ohgami, Akemi Iwamoto, Shizue Yoshioka, Shigeru Tatebe, Yasuaki Hirooka and Masahide Ikeguchi
Division of Surgical Oncology, Department of Surgery, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504 Japan
The phosphatidylinositol-3 kinase (PI3K)-Akt signaling pathway is known to protect a variety of cells from apoptosis. Phospho-Akt (p-Akt) can facilitate cell survival and inactivating pro-apoptotic proteins. The phosphatase and tensin homologue deleted on chromosome ten (PTEN) is a natural biological inhibitor of p-Akt in the PI3K-Akt pathway. The relationship between the expressions of p-Akt and PTEN and pancreatic cancer is unknown. Here, we designed a study to clarify the prognostic significance of p-Akt and PTEN expression in patients with pancreatic cancer. Immunohistochemical analysis of p-Akt and PTEN protein was performed on 51 specimens of pancreatic cancer. The expression of p-Akt was detected in 32 patients (62.7%). The expression of p-Akt was frequently detected in patients with advanced stage pancreatic cancer (P = 0.0233). Patients with p-Akt-positive tumors had significantly worse prognoses than those with p-Akt-negative tumors (overall survival; 11.3% versus 25.7%). The expression of PTEN was detected in 26 patients (51.0%). Patients with PTEN-positive tumors had significantly better prognoses than those with PTEN-negative tumors (overall survival; 29.9% versus 0%). Patients with p-Akt-positive and PTEN-negative tumors had significantly worse prognoses than those with p-Akt-negative and PTEN-positive tumors (overall survival; 0% versus 39.1%). Multivariate analysis revealed that expression of p-Akt was an independent prognostic factor as well as arterial invasion and lymph node metastasis. The expression of p-Akt and PTEN proteins determined by immunohistochemistry may be a new method for predicting the prognosis of patients with pancreatic cancer.
Key words: immunohistochemistry; pancreatic cancer; phosphatase and tensin homologue deleted on chromosome ten; phosphorylated-Akt