Deepti Dhall

TL1A (TNFSF15) Regulates the Development of Chronic Colitis by Modulating Both T-Helper 1 and T-Helper 17 Activation

BACKGROUND & AIMS TL1A is a tumor necrosis factor-like molecule that mediates a strong costimulation of T-helper (T(H)) 1 cells. Expression of TL1A is increased in the mucosa of Crohns disease patients and murine models of ileitis. The aim of this study was to determine the possible role of TL1A in chronic intestinal inflammation. METHODS We used dextran sodium sulfate (DSS)-induced chronic colitis to investigate the effects of TL1A on the development of colitis. The cytokine profile in the gut-associated lymphoid tissue (GALT) was measured. Neutralizing anti-TL1A antibodies were injected intraperitoneally into DSS-induced chronic colitis and G protein alphai2(-/-) T-cell transfer colitis models. Severity of colitis was evaluated by body weight, colon length, histology, and cytokine production. RESULTS DSS-induced chronic colitis was characterized by the infiltration of CD4(+) T cells. TL1A, death receptor 3, interferon (IFN)-gamma, and interleukin (IL)-17 were increased significantly in GALT of DSS-treated mice. TL1A up-regulated both IFN-gamma production from T(H)1 cells and IL-17 production from T(H)17 cells in GALT CD4(+) T cells. Furthermore, IFN-gamma and IL-17 production from CD4(+) T cells, induced by IL-12 and IL-23 respectively, was enhanced synergistically by combination with TL1A. Anti-TL1A antibody prevented chronic colitis and attenuated established colitis by down-regulation of both T(H)1 and T(H)17 activation. CONCLUSIONS Our results reveal that TL1A is an important modulator in the development of chronic mucosal inflammation by enhancing T(H)1 and T(H)17 effector functions. The central role of TL1A represents an attractive, novel therapeutic target for the treatment of Crohns disease patients.

Pathologic Classification and Clinical Behavior of the Spectrum of Goblet Cell Carcinoid Tumors of the Appendix

Appendiceal tumors exhibiting both neuroendocrine and glandular differentiation are uncommon and have caused difficulty in pathologic classification, prediction of prognosis, and clinical management. Previously, such lesions have been variously designated as adenocarcinoid, goblet cell carcinoid (GCC), and mixed adenocarcinoma carcinoid. In this study, we undertook a retrospective investigation of 63 such cases and classified them as typical GCC (group A) and adenocarcinoma ex GCC on the basis of the histologic features of the tumor at the primary site. The adenocarcinoma ex GCC group was further divided into signet ring cell type (group B) and poorly differentiated adenocarcinoma type (group C). The clinical characteristics and prognosis were compared within these groups and with conventional de novo appendiceal adenocarcinomas. Both groups A and B tumors shared a similar immunoprofile, which included generally focal immunoreactivity for neuroendocrine markers, and a normal intestinal type mucin glycoprotein profile (negative MUC1 expression and preserved MUC2 immunoreactivity). The proliferative index was relatively low in these tumors and slightly increased from groups A to B tumors (11% to 16%). Both β-catenin and E-cadherin exhibited a normal membranous staining pattern in groups A and B tumors. The poorly differentiated adenocarcinomas ex GCC (group C) demonstrated abnormal p53 and β-catenin immunoreactivity. The mean follow-up time was 49±5 (SE) months. The overall disease-specific survival for all subtypes was 77%, with 46% of patients without evidence of disease and 31% alive with disease. The mean survival was 43±7 months. All the patients with clinical stage of I or IIA disease had a favorable outcome after appropriate surgery with or without chemotherapy. Although most patients (63%) with GCC presented at an advanced clinical stage, their clinical outcome could be differentiated by subclassification of tumors. The stage IV-matched 5-year survival was 100%, 38%, and 0% for groups A, B, and C, respectively. In conclusion, GCC is a distinctive appendiceal neoplasm that exhibits unique pathologic features and clinical behavior. They display a spectrum of histologic features and possess the potential to transform to an adenocarcinoma phenotype of either signet ring cell or poorly differentiated adenocarcinoma types. Careful evaluation of the morphologic features of GCCs and appropriate pathologic classification are crucial for clinical management and prediction of outcome. Surgical management with right hemicolectomy is recommended after appendectomy for most cases, particularly those with an adenocarcinoma component (groups B and C).

Is nonsmall cell type high-grade neuroendocrine carcinoma of the tubular gastrointestinal tract a distinct disease entity?

Although small cell carcinoma of the gastrointestinal (GI) tract is well-recognized, nonsmall cell type high-grade neuroendocrine carcinoma (HGNEC) of this site remains undefined. At the current time, neither the World Health Organization nor American Joint Committee on Cancer includes this condition in the histologic classifications, and consequently it is being diagnosed and treated inconsistently. In this study, we aimed at delineating the histologic and immunophenotypical spectrum of HGNECs of the GI tract with emphasis on histologic subtypes. Guided primarily by the World Health Organization/International Association for the Study of Lung Cancer criteria for pulmonary neuroendocrine tumors, we were able to classify 87 high-grade GI tract tumors that initially carried a diagnosis of either poorly differentiated carcinoma with or without any neuroendocrine characteristics, small cell carcinoma, or combined adenocarcinoma—neuroendocrine carcinoma into the following 4 categories. The first was small cell carcinoma (n=23), which had features typical of pulmonary small cell carcinoma, although the cells tended to have a more round nuclear contour. The second was large cell neuroendocrine carcinoma (n=31), which had a morphology similar to its pulmonary counterpart and showed positive immunoreactivity for either chromogranin (71%) or synaptophysin (94%) or both. The third was mixed neuroendocrine carcinoma (n=11), which had intermediate histologic features (eg, cells with an increased nuclear/cytoplasmic ratio but with apparent nucleoli), and positive immunoreactivity for at least 1 neuroendocrine marker. The fourth was poorly differentiated adenocarcinoma (n=17). In addition, 5 of the 87 tumors showed either nonsmall cell type neuroendocrine morphology (n=3) or immunohistochemical reactivity for neuroendocrine markers (n=2), but not both. Further analysis showed that most HGNECs arising in the squamous lined parts (esophagus and anal canal) were small cell type (78%), whereas most involving the glandular mucosa were large cell (53%) or mixed (82%) type; associated adenocarcinomas were more frequent in large cell (61%) or mixed (36%) type than in small cell type (26%); and focal intracytoplasmic mucin was seen only in large cell or mixed type. As a group, the 2-year disease-specific survival for patients with HGNEC was 25.4% (median follow-up time, 11.3 mo). No significant survival difference was observed among the different histologic subtypes. In conclusion, our study demonstrates the existence of both small cell and nonsmall cell types of HGNEC in the GI tract, and provides a detailed illustration of their morphologic spectrum. There are differences in certain pathologic features between small cell and nonsmall cell types, whereas the differences between the subtypes of nonsmall cell category (large cell versus mixed) are less distinct. Given the current uncertainty as to whether large cell neuroendocrine carcinoma is as chemosensitive as small cell carcinoma even in the lung, our data provide further evidence in favor of a dichotomous classification scheme (small cell vs. nonsmall cell) for HGNEC of the GI tract. Separation of nonsmall cell type into large cell and mixed subtypes may not be necessary. These tumors are clinically aggressive. Prospective studies using defined diagnostic criteria are needed to determine their biologic characteristics and optimal management.

Homozygous P86s Mutation of the Human Glucagon Receptor Is Associated With Hyperglucagonemia, α Cell Hyperplasia, and Islet Cell Tumor

Objective: The goal of the study was to investigate the genetic and molecular basis of a novel syndrome of marked hyperglucagonemia and pancreatic &agr; cell hyperplasia without glucagonoma syndrome. Methods: The glucagon receptor (GCGR) gene and the glucagon gene were sequenced in a patient with hyperglucagonemia and pancreatic &agr; cell hyperplasia without glucagonoma syndrome. Enhanced green fluorescent protein-conjugated wild type (WT) and mutant GCGR were used to characterize the functions of the mutant GCGR. Results: The glucagon gene sequence was normal, but the GCGR sequencing uncovered a homozygous missense mutation, c.256C>T, p.P86S in the extracellular domain of GCGR. When expressed in human embryonic kidney 293 cells, GCGR P86S localized to the plasma membrane but bound 96% less radiolabeled glucagon than WT GCGR. The median effective concentration of glucagon-induced cyclic adenosine monophosphate production was 24 nmol/L for GCGR P86S but 2.4 nmol/L for WT GCGR. The patients &agr; cells also express glucagonlike peptide 1 and pancreatic polypeptide. Conclusions: We hereby report the first homozygous missense mutation in the human GCGR, which is associated with &agr; cell hyperplasia and hyperglucagonemia. This mutation lowers the receptors affinity to glucagon and decreases cyclic adenosine monophosphate production with physiological concentrations of glucagon. Thus, the P86S mutation in GCGR likely causes &agr; cell hyperplasia and hyperglucagonemia.

Well Differentiated Neuroendocrine Tumors with a Morphologically Apparent High Grade Component: A Pathway Distinct from Poorly Differentiated Neuroendocrine Carcinomas

Purpose: Most well-differentiated neuroendocrine tumors (WD-NET) of the enteropancreatic system are low-intermediate grade (G1, G2). Elevated proliferation demonstrated by either a brisk mitotic rate (>20/10 high power fields) or high Ki-67 index (>20%) defines a group of aggressive neoplasms designated as high-grade (G3) neuroendocrine carcinoma (NEC). High-grade NEC is equated with poorly differentiated NEC (PD-NEC) and is associated with a dismal outcome. Progression of WD-NETs to a high-grade neuroendocrine neoplasm very rarely occurs and their clinicopathologic and molecular features need to be characterized. Experimental Design: We investigated 31 cases of WD-NETs with evidence of a component of a high-grade neoplasm. The primary sites included pancreas, small bowel, bile duct, and rectum. Histopathology of the cases was retrospectively reviewed and selected IHC and gene mutation analyses performed. Results: The high-grade component occurred either within the primary tumor (48%) or at metastatic sites (52%). The clinical presentation, radiographic features, biomarkers, and the genotype of these WD-NETs with high-grade component remained akin to those of G1–G2 WD-NETs. The median disease-specific survival (DSS) was 55 months (16–119 months), and 2-year and 5-year DSS was 88% and 49%, respectively—significantly better than that of a comparison group of true PD-NEC (DSS 11 months). Conclusions: Mixed grades can occur in WD-NETs, which are distinguished from PD-NECs by their unique phenotype, proliferative indices, and the genotype. This phenomenon of mixed grade in WD-NET provides additional evidence to the growing recognition that the current WHO G3 category contains both WD-NETs as well as PD-NECs. Clin Cancer Res; 22(4); 1011–7. ©2015 AACR.

Genetic variants synthesize to produce paneth cell phenotypes that define subtypes of crohn's disease

BACKGROUND & AIMS Genetic susceptibility loci for Crohns disease (CD) are numerous, complex, and likely interact with undefined components of the environment. It has been a challenge to link the effects of particular loci to phenotypes of cells associated with pathogenesis of CD, such as Paneth cells. We investigated whether specific phenotypes of Paneth cells associated with particular genetic susceptibility loci can be used to define specific subtypes of CD. METHODS We performed a retrospective analysis of 119 resection specimens collected from patients with CD at 2 separate medical centers. Paneth cell phenotypes were classified as normal or abnormal (with disordered, diminished, diffuse, or excluded granule phenotypes) based on lysozyme-positive secretory granule morphology. To uncover the molecular basis of the Paneth cell phenotypes, we developed methods to determine transcriptional profiles from whole-thickness and laser-capture microdissected, formalin-fixed, paraffin-embedded tissue sections. RESULTS The proportion of abnormal Paneth cells was associated with the number of CD-associated NOD2 risk alleles. The cumulative number of NOD2 and ATG16L1 risk alleles had an additive effect on the proportion of abnormal Paneth cells. Unsupervised clustering analysis of demographic and Paneth cell data divided patients into 2 principal subgroups, defined by high and low proportions of abnormal Paneth cells. The disordered and diffuse abnormal Paneth cell phenotypes were associated with an altered transcriptional signature of immune system activation. We observed an inverse correlation between abnormal Paneth cells and presence of granuloma. In addition, high proportions of abnormal Paneth cells were associated with shorter time to disease recurrence after surgery. CONCLUSIONS Histologic analysis of Paneth cell phenotypes can be used to divide patients with CD into subgroups with distinct pathognomonic and clinical features.

Ki-67 proliferative index predicts progression-free survival of patients with well-differentiated ileal neuroendocrine tumors

Ki-67 proliferative index (Ki-67 index) is suggested to be an important prognostic variable and is included as one of the grading parameters for neuroendocrine tumors. The present study was undertaken to determine the usefulness of the Ki-67 index and the corresponding tumor grade in predicting progression-free survival (PFS) of patients with ileal well-differentiated neuroendocrine tumors (wNETs). Tumors from 57 patients with ileal wNETs were studied. Immunohistochemical staining for Ki-67 was performed on the primary as well as selected metastatic tumors and quantitated by computer-assisted image analysis using the Ariol system. The tumors were graded based on mitotic activity and Ki-67 index. Clinical and pathological variables affecting the PFS were analyzed. There were 29 women and 28 men, with a mean age of 59 years. At the time of initial presentation, 8 patients (14%) had localized disease (stages I and II), 29 patients (51%) had regional (nodal/mesenteric) spread (stage III), and 20 patients (35%) had distant metastasis (stage IV). Twelve patients experienced disease progression during subsequent follow-up. Patients with initial stage IV disease were more likely to experience disease progression (P = .005). Additionally, higher histological grade (as determined by Ki-67 index >2%) was associated with a decreased PFS (P = .001). Ki-67 index greater than 2% at either the primary site or the metastatic site was found to be the only significant predictor of PFS after consideration of all other variables in an adjusted analysis. In conclusion, the Ki-67 index predicts PFS of patients with ileal wNETs.

S100P, von Hippel-Lindau gene product, and IMP3 serve as a useful immunohistochemical panel in the diagnosis of adenocarcinoma on endoscopic bile duct biopsy.

Histopathologic distinction between benign and malignant bile duct epithelial lesions on endoscopic biopsies can be extremely challenging because of limited material, crush artifact, and compounding inflammatory and/or reactive changes particularly after stent placement. In this study, a total of 72 endoscopic bile duct biopsies, including 40 adenocarcinomas and 32 benign cases, were immunohistochemically examined for the expression of S100P, von Hippel-Lindau gene product (pVHL), and IMP3 to evaluate their diagnostic value. The results showed that 36 adenocarcinomas (90%) exhibited strong nuclear and cytoplasmic staining for S100P, of which 30 (83.3%) showed diffuse immunoreactivity. Intermediate to strong cytoplasmic staining for IMP3 was demonstrated in 31 tumors (77.5%) (15 diffuse, 16 focal). Completely negative staining for pVHL was observed in 37 adenocarcinomas. In the remaining 3 tumors, focal (1) or diffuse (2) membranous and cytoplasmic pVHL immunoreactivity was detected. Twenty-eight tumors (70%) showed a S100P+/IMP3+/pVHL- staining pattern, 6 (15%) with a S100P+/IMP3-/pVHL- pattern, and 2 (5%) with a S100P-/IMP3+/pVHL- pattern. All 32 benign biopsies were completely negative for IMP3 with the exception of 2 cases with focal dysplasia where focal immunoreactivity was observed. Thirty benign biopsies (93.8%) were positive for pVHL with a diffuse staining pattern observed in 28 cases (93.3%). Eight benign biopsies (25%) showed focal S100P positivity. Twenty-two benign biopsies (68.8%) displayed a S100P-/IMP3-/pVHL+ staining pattern. In conclusion, an immunohistochemical panel consisting of S100P, pVHL, and IMP3 can be helpful in distinguishing adenocarcinoma from reactive epithelial changes on challenging bile duct biopsies. The findings of focal S100P and/or IMP3 expression with reciprocal loss of pVHL immunoreactivity in a few benign biopsies suggest a use of these markers in the detection of early epithelial dysplasia that may be beyond histologic recognition.

Pancreatic Neuroendocrine Tumors in Glucagon Receptor-Deficient Mice

Inhibition of glucagon signaling causes hyperglucagonemia and pancreatic α cell hyperplasia in mice. We have recently demonstrated that a patient with an inactivating glucagon receptor mutation (P86S) also exhibits hyperglucagonemia and pancreatic α cell hyperplasia but further develops pancreatic neuroendocrine tumors (PNETs). To test the hypothesis that defective glucagon signaling causes PNETs, we studied the pancreata of mice deficient in glucagon receptor (Gcgr−/−) from 2 to 12 months, using WT and heterozygous mice as controls. At 2–3 months, Gcgr−/− mice exhibited normal islet morphology but the islets were mostly composed of α cells. At 5–7 months, dysplastic islets were evident in Gcgr−/− mice but absent in WT or heterozygous controls. At 10–12 months, gross PNETs (≥1 mm) were detected in most Gcgr−/− pancreata and micro-PNETs (<1 mm) were found in all (n = 14), whereas the islet morphology remained normal and no PNETs were found in any WT (n = 10) or heterozygous (n = 25) pancreata. Most PNETs in Gcgr−/− mice were glucagonomas, but some were non-functioning. No tumors predominantly expressed insulin, pancreatic polypeptide, or somatostatin, although some harbored focal aggregates of tumor cells expressing one of those hormones. The PNETs in Gcgr−/− mice were well differentiated and occasionally metastasized to the liver. Menin expression was aberrant in most dysplatic islets and PNETs. Vascular endothelial growth factor (VEGF) was overexpressed in PNET cells and its receptor Flk-1 was found in the abundant blood vessels or blood islands inside the tumors. We conclude that defective glucagon signaling causes PNETs in the Gcgr−/− mice, which may be used as a model of human PNETs. Our results further suggest that completely inhibiting glucagon signaling may not be a safe approach to treat diabetes.

Value of Islet 1 and PAX8 in identifying metastatic neuroendocrine tumors of pancreatic origin

Neuroendocrine tumors can present as liver metastases before discovery of the primary tumor. Islet 1 and PAX8 have recently been proposed as markers for neuroendocrine tumors of pancreatic origin. In this study, we compared the utility of Islet 1 and PAX8 in distinguishing pancreatic neuroendocrine tumors from neuroendocrine tumors of other sites and determined the usefulness of an immunohistochemical panel, including TTF1, CDX2, Islet 1 and/or PAX8, in identifying metastatic pancreatic neuroendocrine tumors. A total of 110 primary neuroendocrine tumors (33 pancreatic, 31 pulmonary, 23 ileal, 14 rectal, and 9 gastric) and 73 metastatic neuroendocrine tumors (28 pancreatic, 5 pulmonary, 37 ileal, 1 rectal, 1 colonic, and 1 duodenal) were studied. Islet 1 and PAX8 were positive in 27/33 (82%) and 29/33 (88%), respectively, of primary pancreatic neuroendocrine tumors, and in 19/28 (68%) and 15/28 (54%), respectively, of metastatic pancreatic neuroendocrine tumors. No cases of primary (0/23) or metastatic (0/37) ileal neuroendocrine tumors were positive with either Islet 1 or PAX8. There was Islet 1 positivity in 2/31 (6%) primary pulmonary, 12/14 (86%) primary rectal, and 1/1 metastatic rectal neuroendocrine tumors, and PAX8 positivity in 7/31 (23%) primary pulmonary, 11/14 (79%) primary rectal, and 2/9 (22%) primary gastric neuroendocrine tumors. ROC curve analysis incorporating sensitivity and specificity data of immunohistochemical panels for metastatic pancreatic neuroendocrine tumors showed that a four-stain panel, including Islet 1, PAX8, TTF1, and CDX2 significantly outperformed a three-stain panel composed of PAX8, TTF1, and CDX2 (P=0.019), and also showed a trend for better performance compared with a three-stain panel composed of Islet 1, TTF1, and CDX2 (P=0.072). Both Islet 1 and PAX8 are reliable immunohistochemical markers for pancreatic neuroendocrine tumors and would be useful adjuncts to other markers (TTF1, CDX2) currently used to work up a metastatic neuroendocrine tumor of unknown primary.