Correlation Of Pten Loss And Pi3k/Akt/Mtor Pathway Upregulation With Malignant Peripheral Nerve Sheath Tumor (Mpnst) Development And Outcome

10555 Background: MPNST is an aggressive soft tissue sarcoma often arising from preexisting neurofibromas (NF). Our previous study using murine models demonstrated that PTEN loss and PI3K/AKT/mTOR pathway upregulation is a potential mechanism of malignant transformation. The goal of this study is to determine whether a similar mechanism also drives human MPNST development. Methods: A tissue microarray was created from 144 surgical specimens (MPNST n=58, NF n=51, schwannoma n=11, and normal nerve n=24). Cores were stained in triplicate for PTEN and PI3K pathway-associated markers (PTEN, P-AKT, P-S6, GLUT1, SKP-2), other previously identified alterations (p53, p16, P-ERK and c-Myc) as well as tumor grade biomarkers Ki-67 and cleaved caspase 3. Density, intensity and subcellular localization of each marker were quantified and compared using linear regression and survival analysis was performed using Cox proportional hazards modeling. Results: Consistent with our mouse model study, P-S6, GLUT1 and SKP-2, down...