PI3K pathway and downstream signaling analysis in malignant pleural mesothelioma (MPM).

7057 Background: MPM frequently expresses elevated AKT/mTOR activity. This study explored the expression and phosphorylation status of PTEN, PI3K/AKT and downstream signaling in MPM and its relationship with the patient's (pts) prognosis. Methods: Thirty-three consecutive MPM pts were retrospectively collected from our institution between 2002 and 2009. Paraffin-embedded biopsies were used for immunohistochemical profile quantified through the H-score method. Total and phosphorylated (p) proteins analyzed: PTEN, mTOR, MAPK, AKT, 4EBP-1, eiF4E, S6 and FOXO3a. Staining results of each antibody were compared with clinical features and the results were calculated according to the median H-score. Results: Demographics: male/female (25/8); median age 68 (range 52-83); histology epithelial/no-epithelial (22:11); neutrophil/lymphocyte ratio (NLR) >/≤5 (14/18). All patients were treated with chemotherapy. Median OS was 16.4months. Expression of PTEN, pMAPK, mTOR, 4EBP-1, p4EBP-1, eif4E, peif4E, pAKT, p-S6 and FOXO...