PTEN and pancreatic neuroendocrine tumor: In a global gene expression microarray analysis for a large panel of pancreatic endocrine tumors, the tuberous sclerosis 2 (TSC2), and phosphatase and tensin homolog (PTEN), which are two well-defined mTOR inhibitors, were found to be downregulated in most of the primary tumors, and the disfunction of these two mTOR up-stream regulators could be recognized as a sigh for significantly shortened disease-free and overall survival (35).