This issue is dedicated to the pathologic aspects of commonly encountered GI tumors. Experts in the field offer their perspectives about the histopathology, cytopathology, precursor lesions, and recent advances in molecular pathology, and also provide up-to-date guidance in the application of immunohistochemical and molecular/genetic testing of commonly Inhibitors,research,lifescience,medical encountered GI, liver, and pancreatic tumors, with emphasis on their clinical relevance. In the first article, authors from UCLA review the histopathology and current molecular pathology of colorectal carcinoma and its precursor lesions, with emphasis on their clinical relevance (1). Next, investigators from Harbor-UCLA Medical Center

discuss the role played by cell cycle arrest, TLR signaling macrophages and stem cell transformation to form cancer stem cells, and the significance of ballooned hepatocytes that form Mallory-Denk bodies as progenitor pre-cancer cells in the pathogenesis of the transformation of alcohol liver disease to hepatocellular carcinoma (ALD/HCC) (2). Chen and colleagues, Inhibitors,research,lifescience,medical from UC Davis, bring us up to date on the current classification of pancreatic neuroendocrine tumors (PNTs), with insight into genetic

Inhibitors,research,lifescience,medical and molecular changes related to PNT subtypes and their clinical relevance (3). Zhao (UC Irvine) and Yue (LabCorp) update us on gastrointestinal stromal tumors (GIST), including their epidemiology, pathogenesis and genetics, diagnosis, role of molecular analysis, prognostic factors, and management strategies (4). Next, groups from Loma Linda University and UC Davis provide Inhibitors,research,lifescience,medical us with an update on primary

gastrointestinal lymphomas and related neoplasms with respect to their pathogenesis, morphology, ATM inhibitor drugs immunophenotype, molecular and genetic features, and prognostic factors (5). Following are reviews Inhibitors,research,lifescience,medical by teams from Guangdong General Hospital, China, and Loma Linda University, USA, discussing the association between obesity and esophageal cancer (6), and providing an update on Barrett’s esophagus, including current diagnostic criteria, clinical surveillance and promising endoscopic techniques for identifying patients at risk for malignancy (7). The next two articles, by teams from UC Davis and Loma Linda University and AmeriPath General Florida and Memorial Hospital of Jacksonville, Florida, educate us on the current classification of gastric cancer, including histologic features and Annual Review of Biophysics genetic and molecular phenotypes; they clarify the characteristics of each subtype and highlight the potential for improving early diagnosis, prevention, and treatment (8,9). Advances in current understanding of molecular tumorigenesis and related targeted neoadjuvant therapeutic markers are also discussed, along with the application of immunohistochemical and molecular studies. The final two articles apply to GI tumors generally.