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Deshpande, Vikram

The molecular events in chordoma pathogenesis have not been fully delineated, particularly with respect to copy number changes. Understanding copy number alterations in chordoma may reveal critical disease mechanisms that could be exploited for tumor classification and therapy. We report the copy number analysis of 21 sporadic chordomas using array comparative genomic hybridization (CGH). Recurrent copy changes were further evaluated with immunohistochemistry, methylation specific PCR, and quantitative real-time PCR. Similar to previous findings, large copy number losses, involving chromosomes 1p, 3, 4, 9, 10, 13, 14, and 18, were more common than copy number gains. Loss of CDKN2A with or without loss of CDKN2B on 9p21.3 was observed in 16/20 (80%) unique cases of which six (30%) showed homozygous deletions ranging from 76 kilobases to 4.7 megabases. One copy loss of the 10q23.31 region which encodes PTEN was found in 16/20 (80%) cases. Loss of CDKN2A and PTEN expression in the majority of cases was not attributed to promoter methylation. Our sporadic chordoma cases did not show hotspot point mutations in some common cancer gene targets. Moreover, most of these sporadic tumors are not associated with T (brachyury) duplication or amplification. Deficiency of CDKN2A and PTEN expression, although shared across many other different types of tumors, likely represents a key aspect of chordoma pathogenesis. Sporadic chordomas may rely on mechanisms other than copy number gain if they indeed exploit T/ brachyury for proliferation.

How adult tissue stem and niche cells respond to the nutritional state of an organism is not well understood. Here we find that Paneth cells, a key constituent of the mammalian intestinal stem-cell (ISC) niche, augment stem-cell function in response to calorie restriction. Calorie restriction acts by reducing mechanistic target of rapamycin complex 1 (mTORC1) signalling in Paneth cells, and the ISC-enhancing effects of calorie restriction can be mimicked by rapamycin. Calorie intake regulates mTORC1 in Paneth cells, but not ISCs, and forced activation of mTORC1 in Paneth cells during calorie restriction abolishes the ISC-augmenting effects of the niche. Finally, increased expression of bone stromal antigen 1 (Bst1) in Paneth cells—an ectoenzyme that produces the paracrine factor cyclic ADP ribose—mediates the effects of calorie restriction and rapamycin on ISC function. Our findings establish that mTORC1 non-cell-autonomously regulates stem-cell self-renewal, and highlight a significant role of the mammalian intestinal niche in coupling stem-cell function to organismal physiology.

Background: Lymph node metastases are prognostically significant in pancreatic ductal adenocarcinoma. Little is known about the significance of direct lymph node invasion. Aim: The aim of this study is to find out whether direct lymph node invasion has the same prognostic significance as regional nodal metastases. Methods: Retrospective review of patients resected between 1/1/1993 and 7/31/2008. “Direct” was defined as tumor extension into adjacent nodes, and “regional” was defined as metastases to peripancreatic nodes. Results: Overall, 517 patients underwent pancreatic resection for adenocarcinoma, of whom 89 had one positive node (direct 26, regional 63), and 79 had two positive nodes (direct 6, regional 68, both 5). Overall, survival of node-negative patients was improved compared to patients with positive nodes (N0 30.8 months vs. N1 16.4 months; p < 0.001). There was no survival difference for patients with direct vs. regional lymph node invasion (p = 0.67). Patients with one positive node had a better overall survival compared to patients with ≥2 positive nodes (22.3 and 15 months, respectively; p < 0.001). The lymph node ratio (+LN/total LN) was prognostically significant after Cox regression (p < 0.001). Conclusions: Isolated direct invasion occurs in 20% of patients with one to two positive nodes. Node involvement by metastasis or by direct invasion are equally significant predictors of reduced survival. Both the number of positive nodes and the lymph node ratio are significant prognostic factors.

Autoimmune pancreatitis (AIP) shows a unique spectrum of histologic features and commonly presents with an abundant IgG4-positive (IgG4+) plasma cell infiltration. However, differentiating AIP from other mass lesions, particularly pancreatic cancer [invasive ductal carcinoma (IDC)] can be clinically challenging. In this study, we evaluated the validity of IgG4 and IgG immunohistochemistry of ampullary and periampullary tissue for the diagnosis of AIP. Our study group consisted of 14 resected AIP cases with appropriate ampullary sections. Superficial ampullary tissue and "shouldering" duodenal mucosa were evaluated for several histologic variables. Immunohistochemistry for IgG4 and IgG was performed. The number of IgG4 and IgG-positive plasma cells was counted and an IgG4+ to IgG+ plasma cells ratio (IgG4/IgG ratio) was evaluated. A control cohort was composed of IDC (n=30) and chronic pancreatitis (CP) (n=29). Although an overlap was present between the groups, the overall inflammation and number of plasma cells in and around the ampulla was significantly increased in AIP compared with CP and IDC. Furthermore, although there was some overlap in the crude number of IgG4+ plasma cells of the ampullary and duodenal tissue between AIP, IDC, and CP, an IgG4/IgG ratio, especially of the ampulla, seems diagnostically useful in differentiating AIP from other "mass forming" lesions. When a cut-off of 0.10 was applied, the diagnostic sensitivity and specificity of the ampullary IgG4/IgG ratio was 86% and 95%, respectively. In conclusion, evaluation of ampullary histology and IgG4/IgG ratio might be proven beneficial in discriminating AIP from other mass forming pancreatic lesions.

Introduction: A histologic diagnosis of chronic colitis raises a relatively limited differential diagnosis that includes inflammatory bowel disease, long-standing infections, and chronic ischemia. In routine clinical practice, inflammatory bowel disease accounts for the majority of cases of chronic colitis. Although a variety of drug-induced injury patterns in the colon have been recognized, there are few well-documented examples of drug-induced chronic colitis. In this study, we report the clinical, histologic, and follow-up data on 17 cases of histologically documented cases of chronic colitis in which a definitive etiologic factor could not be identified. Methods: Using our electronic databases we recorded all cases of chronic colitis in adults over an 8-year period. Patients with a history (prior or subsequent) of inflammatory bowel disease were excluded. Cases showing histologic features of ischemic, pseudomembranous, or granulomatous colitis were excluded. The biopsies were evaluated and semiquantitatively scored for established histologic features of activity and chronicity. The clinical, endoscopic, and follow-up data, including drug usage, was recorded. Results: There were 10 males and 7 females and the mean age was 59 years. The majority of cases involved the cecum or ascending colon (16 of 17 cases). A majority of patients were asymptomatic (n=11), and in others, indications for colonoscopy were occult blood (n=3), hematochezia (n=2), and melena (n=1). The most common mucosal abnormality was erythema (n=10), ulcers (n=3), congestion (n=3), and edematous mucosa (n=1). All cases showed histologic features of chronicity and showed either basal plasmacytosis (94%) or crypt architectural distortion (94%). Eight (47%) patients reported nonsteroidal anti-inflammatory drugs (NSAID) use. Withdrawal of NSAIDs in 2 cases resulted in normalization of the colonic mucosa. On follow-up, all 17 patients were asymptomatic (median follow-up 42.8 mo) and did not progress to inflammatory bowel disease. Conclusions: We report a series of 17 histologically documented cases of incidental chronic colitis without a conventional etiology. However, both the frequent usage of NSAIDs, and normalization of mucosal changes after withdrawal of this drug suggest that NSAIDs may account for this cecal-based chronic colitis. The awareness of this histologically dramatic but clinically innocuous form of chronic colitis may avoid errors in mucosal biopsy diagnosis.

Objective: To determine whether intraductal papillary mucinous neoplasms of the pancreas (IPMNs) have a different genetic background compared with ductal adenocarcinoma (PDAC). Summary Background Data: The biologic and clinical behavior of IPMNs and IPMN-associated adenocarcinomas is different from PDAC in having a less aggressive tumor growth and significantly improved survival. Up to date, the molecular mechanisms underlying the clinical behavior of IPMNs are incompletely understood. Methods: 128 cystic pancreatic lesions were prospectively identified during the course of 2 years. From the corresponding surgical specimens, 57 IPMNs were separated and subdivided by histologic criteria into those with low-grade dysplasia, moderate dysplasia, high-grade dysplasia, and invasive cancer. Twenty specimens were suitable for DNA isolation and subsequent performance of array CGH. Results: While none of the IPMNs with low-grade dysplasia displayed detectable chromosomal aberrations, IPMNs with moderate and high-grade dysplasia showed frequent copy number alterations. Commonly lost regions were located on chromosome 5q, 6q, 10q, 11q, 13q, 18q, and 22q. The incidence of loss of chromosome 5q, 6q, and 11q was significantly higher in IPMNs with high-grade dysplasia or invasion compared with PDAC. Ten of 13 IPMNs with moderate dysplasia or malignancy had loss of part or all of chromosome 6q, with a minimal deleted region between linear positions 78.0 and 130.0. Conclusions: This study is the first to use array CGH to characterize IPMNs. Recurrent cytogenetic alterations were identified and were different than those described in PDAC. Array CGH may help distinguish between these 2 entities and give insight into the differences in their biology and prognosis.

Gastric epithelial dysplasia (GED) can be morphologically categorized into adenomatous (or intestinal) and foveolar (or gastric) types. Although limited genetic differences have been demonstrated between these subtypes, the expression of various mucins has not been systematically evaluated in this context. Endoscopic mucosal resections from 69 cases of GEDs were evaluated for the expression of MUC2, MUC5AC, MUC6, and CD10. The results were correlated with morphologic categorization and clinicopathologic parameters. GED was classified as adenomatous, foveolar, or hybrid (showing features of both types), on the basis of histologic evaluation. The neighboring intestinal metaplasia (IM) was also evaluated. An adenomatous morphology was seen in 45%, hybrid type in 33.3%, and a “pure” foveolar type was seen in 21.7% of the cases. Foveolar GED was often depressed/flat on endoscopy and showed a statistically significant association with high-grade morphology (P=0.046). Immunohistochemistry confirmed the histologic stratification. The foveolar and hybrid types were more often positive for MUC5AC (P=0.0001 for both) and negative for CD10 (P=0.019 and 0.016, respectively) as compared with adenomatous GED. High-grade morphology was associated with MUC5AC expression regardless of the morphologic phenotype (P=0.026). Foveolar (73.3%) and hybrid (86.9%) GEDs were associated more often with IM showing a retained expression of gastric type mucin than adenomatous GED (29%) (P<0.01 for both). In contrast, adenomatous type (58.1%) of GED was significantly associated with IM showing a complete intestinal phenotype (CD10+) compared with the foveolar (13.3%) and hybrid types (17.4%) of GED (P=0.005 for both comparisons). In conclusion, our study indicates that foveolar and adenomatous types of GED have distinct clinicopathologic features, mucin profiles, and association with different types of IM.

IgG4-related disease (IgG4-RD) is a multiorgan inflammatory disease in which diverse organ manifestations are linked by common histopathological and immunohistochemical features. Prospective studies of IgG4-RD patients are required to clarify the natural history, long-term prognosis, and treatment approaches in this recently recognized condition. Patients with IgG4-RD have different organ manifestations and are followed by multiple specialties. Divergent approaches to the assessment of patients can complicate the interpretation of studies, emphasizing the critical need for validated outcome measures, particularly assessments of disease activity and response to treatment. We developed a prototype IgG4-RD Responder Index (IgG4-RD RI) based on the approach used in the development of the Birmingham Vasculitis Activity Score for Wegener's granulomatosis (BVAS/WG). The IgG4-RD RI was refined by members of the International IgG4-RD Symposium Organizing Committee in a paper case exercise. The revised instrument was applied retrospectively to fifteen IgG4-RD patients at our institution. Those scores were compared to physician's global assessment scale for the same visits. This paper describes the philosophy and goals of the IgG4-RD RI, the steps in the development of this instrument to date, and future plans for validation of this instrument as an outcome measure.

The distinction of Crohn's disease from ulcerative colitis is based on clinical, endoscopic, radiological, and histological findings, a paradigm that remains unchanged despite the advent of new understanding of the immunological and genetic basis of inflammatory bowel disease. There is a strong correlation between inflammatory bowel disease, predominantly ulcerative colitis, and autoimmune pancreatitis. We hypothesized that colonic biopsies from patients with inflammatory bowel disease would demonstrate increased numbers of IgG4-positive plasma cells and that this elevation might be restricted to ulcerative colitis. We examined a cohort of 78 cases of inflammatory bowel disease: 50 ulcerative colitis and 38 Crohn's disease. We identified treatment-naive biopsies. Additionally, four cases of inflammatory bowel disease associated with autoimmune pancreatitis and 15 cases of lymphocytic/collagenous colitis were also identified. Immunohistochemical stains for IgG4 were performed. Biopsies from patients with ulcerative colitis showed significantly higher numbers of IgG4-bearing plasma cells than those with Crohn's disease (mean IgG4 counts per high-power field (hpf) 9.8 vs 2.8, P=0.001). Samples from 19 (38%) ulcerative colitis patients had IgG4 counts >10/hpf, compared with only two (5%) patients with Crohn's disease; the sensitivity and specificity of a cutoff at 10 IgG4-positive plasma cells per hpf was 38 and 95%, respectively. Among individuals <18 years, there were no statistically differences in the IgG4 counts between the two subforms of inflammatory bowel disease. Among adult patients, a cutoff of 5 IgG4+ plasma cells distinguished ulcerative colitis from Crohn's disease with a sensitivity of 53% and specificity of 83%. In comparison to inflammatory bowel disease, patients with lymphocytic/collagenous colitis showed significantly lower numbers of IgG4-positive plasma cells (P=0.0001). Ulcerative colitis with pancolitis showed higher numbers of IgG4-bearing plasma cells (mean IgG4 12.8 vs 5.8 per hpf; P=0.09). An immunohistochemical stain for IgG4 may aid in making the distinction between ulcerative colitis and Crohn's disease (with exclusion of the pediatric cases), albeit with a relatively low sensitivity. This study also provides additional support to the hypothesis that a subset of ulcerative colitis cases is associated with a Th2 response.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly desmoplastic tumor with a dismal prognosis for most patients. Fibrosis and inflammation are hallmarks of tumor desmoplasia. We have previously demonstrated that preventing the activation of pancreatic stellate cells (PSCs) and alleviating desmoplasia are beneficial strategies in treating PDAC. Metformin is a widely used glucose-lowering drug. It is also frequently prescribed to diabetic pancreatic cancer patients and has been shown to associate with a better outcome. However, the underlying mechanisms of this benefit remain unclear. Metformin has been found to modulate the activity of stellate cells in other disease settings. In this study, we examine the effect of metformin on PSC activity, fibrosis and inflammation in PDACs. Methods/Results In overweight, diabetic PDAC patients and pre-clinical mouse models, treatment with metformin reduced levels of tumor extracellular matrix (ECM) components, in particular hyaluronan (HA). In vitro, we found that metformin reduced TGF-ß signaling and the production of HA and collagen-I in cultured PSCs. Furthermore, we found that metformin alleviates tumor inflammation by reducing the expression of inflammatory cytokines including IL-1β as well as infiltration and M2 polarization of tumor-associated macrophages (TAMs) in vitro and in vivo. These effects on macrophages in vitro appear to be associated with a modulation of the AMPK/STAT3 pathway by metformin. Finally, we found in our preclinical models that the alleviation of desmoplasia by metformin was associated with a reduction in ECM remodeling, epithelial-to-mesenchymal transition (EMT) and ultimately systemic metastasis. Conclusion: Metformin alleviates the fibro-inflammatory microenvironment in obese/diabetic individuals with pancreatic cancer by reprogramming PSCs and TAMs, which correlates with reduced disease progression. Metformin should be tested/explored as part of the treatment strategy in overweight diabetic PDAC patients.