Person:

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.

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.

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.

BACKGROUND: Chronic sclerosing sialadenitis is a fibroinflammatory disease of the salivary glands, characteristically of the submandibular gland. One prior Asian study proposed that chronic sclerosing sialadenitis is a part of the spectrum of IgG4-associated disease. This association has not been confirmed in Western populations. We therefore, investigated the relationship between IgG4 and chronic sclerosing sialadenitis, and compared the histomorphologic features of this condition with those of chronic sialadenitis-not otherwise specified, Sjögren syndrome, and lymphoepithelial sialadenitis. MATERIALS AND METHODS: We evaluated 13 cases of chronic sclerosing sialadenitis and compared them with 15 cases of chronic sialadenitis-not otherwise specified, 8 lip biopsies from individuals with Sjögren syndrome, and 4 cases of lymphoepithelial sialadenitis. Immunohistochemistry for IgG, and IgG4 was carried out. IgG4-positive plasma cells were quantified and the IgG4/IgG ratio was calculated. RESULTS: Seven patients with chronic sclerosing sialadenitis were female and 6 were male. Their mean age was 61 years (range: 27 to 80). Twelve chronic sclerosing sialadenitis cases involved the submandibular gland (bilaterally in 3) and in 1 there was a parotid lesion. Three of these 12 cases had manifestations of IgG4-associated systemic disease. Morphologically these specimens had preservation of lobular architecture, hypercellular interlobular fibrosis, florid lymphoid hyperplasia, and numerous plasma cells. Obliterative phlebitis was observed in 6 cases. The histologic features of chronic sclerosing sialadenitis were reminiscent of autoimmune pancreatitis, and were either not observed or were present only focally in cases of chronic sialadenitis, Sjögren syndrome, and lymphoepithelial sialadenitis.Eleven of 12 evaluable cases showed an increased number of IgG4 plasma cells with a mean of 229/high-power field (HPF) (range 75 to 608) and an overall IgG4/IgG ratio of 0.86 (range 0.5 to 1). The only patient whose biopsy lacked IgG4-positive plasma cells had pathologic evidence of cytomegalovirus infection. Chronic sclerosing sialadenitis cases, in comparison with the other 3 groups studied, showed a significantly higher number of IgG4 positive plasma cells (P<0.05). Patients with chronic sialadenitis-not otherwise specified had a median number of only 16 IgG4-positive plasma cells/HPF (range 2 to 44), with an IgG4/IgG ratio of 0.14 (range 0.02 to 0.28). The Sjögren syndrome patients had a median of 1 IgG4-positive plasma cell/HPF (range 0 to 3), with an IgG4/IgG ratio of 0.02 (range 0 to 0.07). Patients with lymphoepithelial sialadenitis had a median of 0 IgG4-positive plasma cells per HPF. CONCLUSION: Chronic sclerosing sialadenitis has a characteristic morphologic appearance. This morphologic appearance, in conjunction with the elevated IgG4 expression, distinguishes chronic sclerosing sialadenitis from other inflammatory diseases of the salivary glands. Chronic sclerosing sialadenitis belongs to the spectrum of IgG4-related diseases.

Autoimmune pancreatitis (AIP) is a chronic inflammatory disease of the pancreas. Examination of pancreatic resection specimens from patients with AIP has shown that there are 2 subclasses of this disease. However, there is no widely accepted pathologic classification scheme and the clinical significance of such a classification remains to be established. In this study, we revisited the subclassification of AIP and examine whether this provides clinically and prognostically meaningful information. We evaluated 29 pancreatic resection specimens from patients with AIP. Demographic, clinical, and imaging data were recorded, as was evidence of extrapancreatic manifestations. In addition to a detailed and semiquantitative histologic evaluation, immunohistochemistry for IgG4 was performed on pancreatic and extrapancreatic tissues. We also evaluated 48 consecutive cases of chronic pancreatitis, not otherwise specified. The resected specimens could readily be subclassified into 2 subtypes: type 1 (n=11) and type 2 (n=18). In comparison with patients with type 2 disease, patients with type 1 disease were significantly more likely to be males (P=0.09), older (P=0.02), and present with jaundice (P=0.01), and less likely to be associated with abdominal pain (P=0.04). On imaging, the pancreatic tail cut-off sign was exclusively seen in patients with type 2 disease (4 of 10 cases). Hypercellular inflamed interlobular stroma was unique to type 1 pattern (91%), whereas significant ductal injury in the form of microabscesses and ductal ulceration was almost exclusively seen in type 2 pattern (78%). Eight of 10 patients with a type 1 pattern had evidence of a systemic disease. Three patients with type 2 disease had recurrent episodes of pancreatitis after their pancreatic resection. In comparison with the cohort of chronic pancreatitis, not otherwise specified, type 2 AIP cases were less likely to be associated with a history of alcohol abuse, and showed significantly more foci of periductal inflammation and neutrophilic microabscesses. Our review of pancreatic resection specimens shows 2 histologically distinct forms of AIP. Our data support the concept that type 1 AIP is a systemic disease and is the pancreatic manifestation of IgG4-related systemic disease. Type 2 disease is confined to the pancreas. The intensity of the periductal inflammatory infiltrate and the presence of ductal neutrophilic abscesses are features that assist in distinguishing type 2 AIP from chronic pancreatitis, not otherwise specified. Although imperfect, clinical and imaging features may help distinguish the 2 subtypes of AIP. On the basis of these significant differences between the 2 types of AIP, we advocate the position that all subsequent studies attempt to substratify their patients into these 2 groups.

OBJECTIVES: To estimate the risk of malignancy in autoimmune pancreatitis (AIP). METHODS: We examined resected pancreata to compare the prevalence of pancreatic intraepithelial neoplasia (PanIN) in 28 cases of AIP and 30 cases of chronic pancreatitis not otherwise specified (CP-NOS). We also reviewed a cohort of 84 AIP cases. RESULTS: The mean age of the AIP cohort (57 years) was significantly higher than that of the cohort of CP-NOS (47 years) (P = 0.01). Twenty-three cases (82%) of AIP showed PanIN, and 7 cases (25%) showed grade 2 PanIN. Grade 3 PanIN was identified in one case of AIP. There was no statistically significant difference in the number of cases with high-grade PanIN lesions between the cases of type 1 as opposed to type 2 AIP. In comparison to CP-NOS, a comparable percentage of patients with AIP had PanIN (82% of AIP cases vs 63% of CP-NOS cases) (P = NS) and PanIN 2 (25% AIP vs 20% CP-NOS) (P = NS). Of the 84 AIP cases at our institution (mean follow-up, 49 months), 2 cases of pancreatic carcinoma were identified 6 and 10 years after the diagnoses of AIP. CONCLUSIONS: These findings raise concern that AIP is associated with an elevated risk of malignancy and should prompt additional studies.