MicroRNA Expression in Selected Carcinomas of the Gastrointestinal Tract

MicroRNAs (miRNAs) comprise a recently discovered class of small, 18–25 nucleotide, noncoding RNA sequences that regulate gene expression at the posttranscriptional level by binding to and inhibiting the translation of target messenger RNAs (mRNAs). Characteristic patterns of miRNA expression have been described in several malignancies of the gastrointestinal tract, and numerous investigators have demonstrated interactions between specific miRNA species and target oncogenes or tumor-suppressor genes. It is clear that miRNAs play an important role in regulating expression of a number of genes involved in gastrointestinal carcinogenesis, and, thus, these molecules may represent either diagnostic markers of, or therapeutic targets for, some types of malignancy. This paper summarizes the literature regarding miRNA expression in carcinomas of the colon, pancreas, and liver and discusses some of the mechanisms by which these molecules participate in gastrointestinal oncogenesis

doi:10.4061/2011/124608 Review Article MicroRNA Expression in Selected Carcinomas of the Gastrointestinal Tract

Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. MicroRNAs (miRNAs) comprise a recently discovered class of small, 18–25 nucleotide, noncoding RNA sequences that regulate gene expression at the posttranscriptional level by binding to and inhibiting the translation of target messenger RNAs (mRNAs). Characteristic patterns of miRNA expression have been described in several malignancies of the gastrointestinal tract, and numerous investigators have demonstrated interactions between specific miRNA species and target oncogenes or tumorsuppressor genes. It is clear that miRNAs play an important role in regulating expression of a number of genes involved in gastrointestinal carcinogenesis, and, thus, these molecules may represent either diagnostic markers of, or therapeutic targets for, some types of malignancy. This paper summarizes the literature regarding miRNA expression in carcinomas of the colon, pancreas, and liver and discusses some of the mechanisms by which these molecules participate in gastrointestinal oncogenesis. 1

Educational Case: Immune-Related Disorders of the Bowel

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040

What Is the Value of Counting Mast Cells in Gastrointestinal Mucosal Biopsies?

Neoplastic and nonneoplastic mast cell disorders can cause diarrhea, nausea, and abdominal pain that result from heightened release of mast cell mediators. Systemic mastocytosis is characterized by neoplastic mast cell aggregates in the bone marrow and other sites, particularly the skin and gastrointestinal tract. In this situation, extramedullary mast cell aggregates display atypical morphology, with aberrant immunostaining for CD25 in addition to staining for other mast cell markers, such as mast cell tryptase and CD117. Morphologically normal mast cells have also been implicated in nonneoplastic conditions. For example, increased mast cell numbers have been reported in the mucosal biopsy samples from patients with irritable bowel syndrome and hereditary alpha-tryptasemia. Patients with mast cell activation syndrome presumably experience symptoms related to the aberrant elaboration of histamine and other mediators from normal-appearing mast cells present in normal numbers. Unfortunately, similarities in terminology among these biologically distinct clinical conditions have caused considerable diagnostic confusion among clinical colleagues, resulting in frequent requests for pathologists to quantify and characterize mast cells in normal gastrointestinal biopsy samples from patients with diarrheal symptoms. The purpose of this review is to summarize the available data related to mast cell assessment in the gastrointestinal tract and provide pathologists with practical information so that they can help their clinical colleagues manage patients with presumed mast cell disorders

Clinical significance of pathologic abnormalities in biopsy samples from the appendiceal orifice

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/170899/1/his14418_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/170899/2/his14418.pd

Measuring depth of invasion of submucosa- - - invasive adenocarcinoma in oesophageal endoscopic specimens: how good are we?-

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/171205/1/his14566.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/171205/2/his14566_am.pd

NK/T cell non-Hodgkin lymphoma in a HIV-positive patient

NK/T lymphomas have rarely been reported in HIV/AIDS patients. Here we report a case of a 37-year-old woman, with AIDS and a recent diagnosis of Kaposi sarcoma in a mesenteric lymph node, who presented with extra-ocular nerve palsies and gastrointestinal bleeding. A small intestine resection specimen revealed an extra-nodal NK/T cell lymphoma, nasal type. The unique presentation of this rare and aggressive lymphoma in the setting of AIDS and Kaposi sarcoma underscores the importance of maintaining a broad differential diagnosis when evaluating a malignant neoplasm from a HIV-positive patient