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Ralph H Hruban

Publications and source records attributed to Ralph H Hruban.

At least 19 recordsLinked to original sources

Intraductal Papillary Squamous Neoplasm (IPSN) of the Pancreas: Histological and Molecular Characterization of a Novel and Distinct Intraductal Cancer Precursor.

We report 6 intraductal papillary squamous neoplasms (IPSNs) of the pancreas, a rare but distinctive tumor whose biological features remain largely unknown. Five cases were investigated using an integrated approach combining histomorphological evaluation, immunohistochemistry, and multiregional molecular profiling through whole-exome DNA sequencing and whole-transcriptome RNA sequencing. Only targeted DNA sequencing was available on a sixth recently diagnosed case. Histologically, the intraductal lesions were characterized by large, confluent papillae with fibrovascular cores lined by multilayered epithelial cells with diffuse squamous differentiation. All cases harbored a concomitant invasive carcinoma. The associated invasive carcinomas consistently included a pancreatic tubular/ductal adenocarcinoma; in 5 cases, a poorly differentiated squamous cell carcinoma was also present, the proportion/features of which met the diagnostic criteria of adenosquamous carcinoma in 2 of them. Genomic analyses revealed that IPSNs and their matched invasive carcinomas shared the majority of somatic alterations, supporting a shared clonal origin for the 2 components. Activating KRAS mutations and biallelic inactivation of CDKN2A were detected in all cases. Recurrent mutations involved members of the SWI/SNF chromatin-remodeling complex and KMT2D. Additionally, FGFR1 and MYC amplifications were identified in 2 distinct cases (1 case each). Molecular alterations restricted to the invasive component involved mediators of the transforming growth factor-β signaling pathway. Transcriptomic profiling demonstrated a basal-like expression pattern in all IPSNs and squamous cell carcinomas, although in 2 cases, the matched pancreatic tubular/ductal adenocarcinoma shifted toward a classical transcriptomic subtype. In conclusion, through integrated histological assessment and multiregional molecular sequencing, we demonstrate that IPSN represents a bona fide precursor of invasive pancreatic cancer, a new addition to the intraductal neoplasms category. This study challenges the current paradigm that pancreatic squamous epithelium plays no role in the initiation of pancreatic carcinogenesis, providing the first evidence of its involvement in early tumorigenic processes and yielding immediate implications for pancreatic tumor classification and biological understanding.

Humans↗

Multi-omic profiling of intraductal papillary neoplasms of the pancreas reveals distinct patterns and potential markers of progression.

To enable early detection of pancreatic cancer from precancerous lesions, we analyze proteins and glycoproteins from 64 intraductal papillary mucinous neoplasms (IPMNs), 55 cyst fluid samples, 104 pancreatic ductal adenocarcinomas (PDACs), and various types of normal samples using mass spectrometry. High-grade IPMNs show enrichment of glycosylation level and tumor progression pathways compared to low-grade lesions. High-grade IPMN associated proteins, such as PLOD3, IRS2, LGALS9, and Trop-2, are identified and validated using immunolabeling and laser microdissection. Some high-grade associated proteins are also detected in pancreatic cyst fluids, which allows us to link proteins and glycoproteins expressed in neoplastic cells to clinically accessible biospecimens. Altered glycosylation level of extracellular matrix (ECM) proteins is observed in IPMNs compared to normal ducts. Additionally, we identify a subset of IPMNs with PDAC-like features, including elevated expression of ECM proteins. These findings offer insight into progression-associated proteins and emphasize the diagnostic and therapeutic potential of these proteins in pancreatic tumors.

Humans↗

SPARC/osteonectin is a frequent target for aberrant methylation in pancreatic adenocarcinoma and a mediator of tumor-stromal interactions.

Deregulated expression of SPARC/osteonectin, a secreted glycoprotein with multiple biological functions, has been associated with the progression of various cancers. Using microarrays, we previously identified SPARC as one of the genes induced by treatment with a DNA methylation inhibitor in pancreatic cancer cells. We therefore analysed the expression pattern and methylation status of the SPARC gene in pancreatic cancer. Gene expression profiling by oligonucleotide microarray and reverse transcription-PCR analyses demonstrated that SPARC mRNA was expressed in non-neoplastic pancreatic ductal epithelial cells, but was not expressed in a majority of pancreatic cancer cell lines. The loss of SPARC expression was associated with aberrant hypermethylation of its CpG island. Immunohistochemical labeling revealed that the SPARC protein was overexpressed in the stromal fibroblasts immediately adjacent to the neoplastic epithelium in primary pancreatic cancers, but rarely expressed in the cancers themselves. Primary fibroblasts derived from pancreatic cancer strongly expressed SPARC mRNA and secreted SPARC protein into the conditioned media, and treatment of pancreatic cancer cells with exogenous SPARC resulted in growth suppression. SPARC expression in fibroblasts from noncancerous pancreatic tissue was augmented by coculture with pancreatic cancer cells. These findings suggest that SPARC is a frequent target for aberrant methylation in pancreatic cancer and that SPARC expression in fibroblasts adjacent to pancreatic cancer cells is regulated through tumor-stromal interactions.

Adenocarcinoma↗

Identifying tumor origin using a gene expression-based classification map.

Identifying the primary site in cases of metastatic carcinoma of unknown origin has profound clinical importance in managing cancer patients. Although transcriptional profiling promises molecular solutions to this clinical challenge, simpler and more reliable methods for this purpose are needed. A training set of 11 serial analysis of gene expression (SAGE) libraries was analyzed using a combination of supervised and unsupervised computational methods to select a small group of candidate genes with maximal power to discriminate carcinomas of different tissue origins. Quantitative real-time PCR was used to measure their expression levels in an independent validation set of 62 samples of ovarian, breast, colon, and pancreatic adenocarcinomas and normal ovarian surface epithelial controls. The diagnostic power of this set of genes was evaluated using unsupervised cluster analysis methods. From the training set of 21,321 unique SAGE transcript tags derived from 11 libraries, five genes were identified with expression patterns that distinguished four types of adenocarcinomas. Quantitative real-time PCR expression data obtained from the validation set clustered tumor samples in an unsupervised manner, generating a self-organized map with distinctive tumor site-specific domains. Eighty-one percent (50 of 62) of the carcinomas were correctly allocated in their corresponding diagnostic regions. Metastases clustered tightly with their corresponding primary tumors. A classification map diagnostic of tumor types was generated based on expression patterns of five genes selected from the SAGE database. This expression map analysis may provide a reliable and practical approach to determine tumor type in cases of metastatic carcinoma of clinically unknown origin.

Adenocarcinoma↗

Discovery of novel targets for aberrant methylation in pancreatic carcinoma using high-throughput microarrays.

To identify potential targets for aberrant methylation in pancreatic cancer, we analyzed global changes in gene expression profiles of four pancreatic cancer cell lines after treatment with the demethylating agent 5-aza-2'-deoxycytidine (5Aza-dC) and/or the histone deacetylase inhibitor trichostatin A. A substantial number of genes were induced 5-fold or greater by 5Aza-dC alone (631 transcripts), trichostatin A alone (1196 transcripts), and by treatment with both agents (857 transcripts). Four hundred and seventy-five genes were markedly (>5-fold) induced after 5Aza-dC treatment in pancreatic cancer cell lines but not in a nonneoplastic pancreatic epithelial cell line. The methylation status of 11 of these 475 genes was examined in a panel of 42 pancreatic cancers, and all 11 of these genes were aberrantly methylated in pancreatic cancer but rarely, if any, methylated in 10 normal pancreatic ductal epithelia. These genes include UCHL1 (methylated in 100% of 42 pancreatic cancers), NPTX2 (98%), SARP2 (95%), CLDN5 (93%), reprimo (86%), LHX1 (76%), WNT7A (71%), FOXE1 (69%), TJP2 (64%), CDH3 (19%), and ST14 (10%). Three of these 11 genes (NPTX2, SARP2, and CLDN5) were selected for further analysis in a larger panel of specimens, and aberrant methylation of at least one of these three genes was detectable in 100% of 43 primary pancreatic cancers and in 18 of 24 (75%) pancreatic juice samples obtained from patients with pancreatic cancer. Thus, a substantial number of genes are induced by 5Aza-dC treatment of pancreatic cancer cells, and many of them may represent novel targets for aberrant methylation in pancreatic carcinoma.

Adult↗

Fanconi anemia gene mutations in young-onset pancreatic cancer.

Genes of the Fanconi complementation groups [Fanconi anemia (FA) genes] are suggested to be involved in homologous DNA recombination and produce FA when two allelic mutations are inherited. BRCA2 is an FA gene and additionally conveys an inherited risk for breast, ovarian, and pancreatic cancer for individuals carrying a single mutated allele [N. G. Howlett et al., Science (Wash. DC), 297: 606-609, 2002]. Here we report inherited and somatic mutations of FANCC and FANCG present in young-onset pancreatic cancer. This may imply a general involvement of Fanconi genes with an inherited risk of cancer. The known hypersensitivity of Fanconi cells to mitomycin and other therapeutic agents [M. S. Sasaki, Nature (Lond.), 257: 501-503, 1975] suggests a therapeutic utility for a more complete characterization of the DNA repair defects and their causative genetic mutations in pancreatic cancer.

Age Factors↗

Identification of CDH1 germline missense mutations associated with functional inactivation of the E-cadherin protein in young gastric cancer probands.

E-cadherin is involved in the formation of cell-junctions and the maintenance of epithelial integrity. Direct evidence of E-cadherin mutations triggering tumorigenesis has come from the finding of inactivating germline mutations of the gene (CDH1) in hereditary diffuse gastric cancer (HDGC). We screened a series of 66 young gastric cancer probands for germline CDH1 mutations, and two novel missense alterations together with an intronic variant were identified. We then analysed the functional significance of the two exonic missense variants found here as well as a third germline missense variant that we previously identified in a HGDC family. cDNAs encoding either the wild-type protein or mutant forms of E-cadherin were stably transfected into CHO (Chinese hamster ovary) E-cadherin-negative cells. Transfected cell-lines were characterized in terms of aggregation, motility and invasion. We show that a proportion of apparently sporadic early-onset diffuse gastric carcinomas are associated with germline alterations of the E-cadherin gene. We also demonstrate that a proportion of missense variants are associated with significant functional consequences, suggesting that our cell model can be used as an adjunct in deciding on the potential pathogenic role of identified E-cadherin germline alterations.

Adult↗

Evidence of selection for clones having genetic inactivation of the activin A type II receptor (ACVR2) gene in gastrointestinal cancers.

The activin signaling pathway parallels the transforming growth factor (TGF)-beta pathway. Both use extracellular ligands and cell surface receptors that are structurally and functionally related, as well as the same intracellular mediators (SMADs 2-4) to transmit these signals. Members of both pathways have been characterized previously as tumor suppressor genes on the demonstration of inactivating mutations in human neoplasms, e.g., genetic inactivation of the activin type I receptor was reported recently in pancreatic cancer. Here, we present evidence of selection for mutations of the activin A type II receptor (ACVR2) gene during human gastrointestinal carcinogenesis. Two 8-bp polyadenine tracts of the ACVR2 gene are targets for inactivating frameshift mutations in gastrointestinal neoplasms having microsatellite instability (MSI). These mutations are similar to those of the 10-bp polyadenine tract within the TGF-beta type II receptor (TGFBR2), a well-characterized target of frameshift mutations in the same neoplasms. We identified biallelic mutations of ACVR2 in 25 of 28 MSI colorectal and pancreatic cancers. In addition, a mutation in the ACVR2 gene combined with loss of the wild-type allele was found in a non-MSI pancreatic cancer. This evidence is compatible with a high degree of selection for inactivation of the ACVR2 gene in tumorigenesis, supporting ACVR2 as a candidate tumor suppressor gene in gastrointestinal cancers.

Activin Receptors, Type II↗

Exploration of global gene expression patterns in pancreatic adenocarcinoma using cDNA microarrays.

Pancreatic cancer is the fifth leading cause of cancer death in the United States. We used cDNA microarrays to analyze global gene expression patterns in 14 pancreatic cancer cell lines, 17 resected infiltrating pancreatic cancer tissues, and 5 samples of normal pancreas to identify genes that are differentially expressed in pancreatic cancer. We found more than 400 cDNAs corresponding to genes that were differentially expressed in the pancreatic cancer tissues and cell lines as compared to normal pancreas. These genes that tended to be expressed at higher levels in pancreatic cancers were associated with a variety of processes, including cell-cell and cell-matrix interactions, cytoskeletal remodeling, proteolytic activity, and Ca(++) homeostasis. Two prominent clusters of genes were related to the high rates of cellular proliferation in pancreatic cancer cell lines and the host desmoplastic response in the resected pancreatic cancer tissues. Of 149 genes identified as more highly expressed in the pancreatic cancers compared with normal pancreas, 103 genes have not been previously reported in association with pancreatic cancer. The expression patterns of 14 of these highly expressed genes were validated by either immunohistochemistry or reverse transcriptase-polymerase chain reaction as being expressed in pancreatic cancer. The overexpression of one gene in particular, 14-3-3 sigma, was found to be associated with aberrant hypomethylation in the majority of pancreatic cancers analyzed. The genes and expressed sequence tags presented in this study provide clues to the pathobiology of pancreatic cancer and implicate a large number of potentially new molecular markers for the detection and treatment of pancreatic cancer.

Adenocarcinoma↗

Atheroembolism in cardiac surgery.

BACKGROUND: Atheroembolism is a recognized complication of cardiac surgery, but its incidence and various outcomes have not been completely described. A retrospective study was undertaken to better characterize the syndrome. METHODS: Records of 49,377 autopsies and surgical specimens from the Johns Hopkins Hospital between 1973 and 1995 were reviewed. Three hundred twenty-seven patients (0.7%) had an identifiable atheroembolism on histologic examination. Of these patients, 29 (0.2%) had undergone a cardiac surgical procedure within 30 days of autopsy or surgical resection. Patient charts and pathology specimens were reviewed for operative findings, postoperative outcomes, and histology. RESULTS: Six of the 29 patients (21%) had atheroembolism to the heart, 7 patients (24%) had embolism to the central nervous system, 19 patients (66%) had embolism to the gastrointestinal tract, 14 patients (48%) had embolism to one or both kidneys, and 5 patients (17%) had embolism to a lower extremity. Sixteen patients (55%) had atheroembolism in two or more areas. In 6 patients (21%), death was directly attributable to atheroembolism, including intraoperative cardiac failure from coronary embolism (n = 3), massive stroke (n = 2), and extensive gastrointestinal embolization (n = 1). CONCLUSIONS: Atheroembolism in cardiac surgery has a broad spectrum of clinical presentations, including devastating injuries and death. Although the true incidence is probably underestimated in this retrospective study, the high attendant mortality and morbidity of atheroembolism have been documented. Improvements in outcome are likely to be associated with preoperative identification of patients at high risk, modifications of perfusion technique, and interventions to minimize secondary thrombosis and progressive organ ischemia.

Aged↗

Standard vs. radical pancreaticoduodenectomy for periampullary adenocarcinoma: a prospective, randomized trial evaluating quality of life in pancreaticoduodenectomy survivors.

This study was designed to assess the health-related quality of life (QOL) of patients who had been randomly assigned to either standard or radical pancreaticoduodenectomy for periampullary adenocarcinoma. Pancreaticoduodenectomy has been performed in increasing numbers for periampullary adenocarcinoma. The appropriate extent of resection (standard vs. radical [extended]) remains controversial, particularly as concerns survival benefit. Past reports comparing standard vs. radical resection have suggested that the more extensive resection is attended by negative functional outcomes (diarrhea and weight loss) and poorer QOL, diminishing the impact of any possible survival advantage of the radical resection. A prospective, randomized single-institution trial comparing standard pancreaticoduodenectomy (pylorus preservation preferred) to radical pancreaticoduodenectomy (including distal gastrectomy and retroperitoneal lymphadenectomy) evaluated 299 patients with periampullary adenocarcinoma between April 1996 and June 2001. A standard Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-Hep) QOL survey designed for hepatobiliary cancer was sent to 150 of these patients surviving pancreaticoduodenectomy. QOL and functional status were assessed via a series of subscale scores for physical, social, emotional, and functional well-being. A total of 105 QOL surveys (70%) were returned and analyzed, with 55 of the patients having been randomized to the standard group and 50 to the radical group. The patients were evaluated at a mean of 2.2 years after pancreaticoduodenectomy. The two groups were statistically similar with regard to multiple parameters including age at operation (64.6 years), race, intraoperative blood transfusions, pathologic diagnosis and staging, and perioperative complications. The radical group had a significantly higher percentage of men (66% vs. 44%; P = 0.02), a longer operative time (369 minutes vs. 327 minutes; P < 0.001), and a longer postoperative length of hospital stay (13.6 days vs. 10.1 days; P < 0.01). The FACT-Hep total QOL scores were similar between the standard and radical groups: 143.5 vs. 147.3, respectively. Additionally, the individual FACT-G subscale scores evaluating physical (22.1 vs. 23.3), social (24.5 vs. 24.4), emotional (19.2 vs. 19.6), and functional well-being (20.6 vs. 22.4) were comparable between the standard and radical groups. Subgroup analyses based on pathologic diagnosis (pancreatic, ampullary, distal bile duct, etc.) failed to reveal any differences in QOL assessment between the standard and radical pancreaticoduodenectomy groups. Finally, QOL measures were similar when comparing time since operation (<2 years' follow-up vs. >2 years' follow-up) and age (< or =65 years vs. >65 years). This is the largest report comparing QOL assessment in survivors of pancreaticoduodenectomy randomized between standard and radical resection. These data demonstrate no differences in long-term QOL between standard and radical resection. These results imply that no negative long-term QOL measures are associated with radical pancreaticoduodenectomy (as performed in this study) for periampullary adenocarcinoma.

Adenocarcinoma↗

Notch mediates TGF alpha-induced changes in epithelial differentiation during pancreatic tumorigenesis.

Notch signaling regulates cell fate decisions in a wide variety of adult and embryonic tissues. Here we show that Notch pathway components and Notch target genes are upregulated in invasive pancreatic cancer, as well as in pancreatic cancer precursors from both mouse and human. In mouse pancreas, ectopic Notch activation results in accumulation of nestin-positive precursor cells and expansion of metaplastic ductal epithelium, previously identified as a precursor lesion for pancreatic cancer. Notch is also activated as a direct consequence of EGF receptor activation in exocrine pancreas and is required for TGF alpha-induced changes in epithelial differentiation. These findings suggest that Notch mediates the tumor-initiating effects of TG alpha by expanding a population of undifferentiated precursor cells.

Animals↗

Pancreaticoduodenectomy (Whipple resections) in patients without malignancy: are they all 'chronic pancreatitis'?

Pancreaticoduodenectomy (Whipple resection) has evolved into a safe procedure in major high-volume medical centers for the treatment of pancreatic adenocarcinoma and refractory chronic pancreatitis. However, some Whipple resections performed for a clinical suspicion of malignancy reveal only benign disease on pathologic examination. We evaluated the frequency of such Whipple resections without tumor in a large series of pancreaticoduodenectomies and classified the diverse pancreatic and biliary tract diseases present in these specimens. Of 442 Whipple resections performed during 1999-2001, 47 (10.6%) were negative for neoplastic disease and, in 40 cases, had been performed for a clinical suspicion of malignancy. Most Whipple resections revealed benign pancreatic disease, including 8 (17%) alcohol-associated chronic pancreatitis, 4 (8.5%) gallstone-associated pancreatitis, 1 (2.1%) pancreas divisum, 6 (12.8%) "ordinary" chronic pancreatitis of unknown etiology, and 11 (23.4%) lymphoplasmacytic sclerosing pancreatitis. In particular, patients with lymphoplasmacytic sclerosing pancreatitis were all thought to harbor malignancy, whereas only 13 of 19 (68.4%) of Whipple resections showing histologically "ordinary" forms of chronic pancreatitis were performed for a clinical suspicion of malignancy. Benign biliary tract disease, including three cases of primary sclerosing cholangitis, two cases of choledocholithiasis-associated chronic biliary tract disease, and four fibroinflammatory strictures isolated to the intrapancreatic common bile duct, was a common etiology for clinically suspicious Whipple resections (22.5% of cases). Pancreatic intraepithelial neoplasia (PanIN) was a common finding among all pancreata, whether involved by pancreatitis or histologically normal. Overall, PanIN 1A/1B was present in 68.1%, PanIN 2 in 40.4%, and PanIN 3 in just 2.1%. These findings indicate that "benign but clinically suspicious" Whipple resections are relatively common in high-volume centers (9.2%) and reveal a diverse group of clinicopathologically distinctive pancreatic and biliary tract disease.

Adult↗

Eosinophilic pancreatitis and increased eosinophils in the pancreas.

Prominent eosinophilic infiltrates are an unusual finding in the pancreas. Eosinophilic pancreatitis is one rare etiology of pancreatic eosinophilia, but other described causes of eosinophilic infiltrates have also included pancreatic allograft rejection, pancreatic pseudocyst, lymphoplasmacytic sclerosing pancreatitis (LPSP), inflammatory myofibroblastic tumor, and histiocytosis X. In this study we describe the clinicopathologic features of three new cases of eosinophilic pancreatitis and conduct a retrospective 18-year institutional review of the myriad disease processes associated with pancreatic eosinophilia. In the files of the Johns Hopkins Hospital, <1% of all pancreatic specimens had been noted to show increased numbers of eosinophils. Eosinophilic pancreatitis itself was a rare etiology for pancreatic eosinophilia, with only one in-house case over the 18-year study period and two additional referral cases. Other disease processes associated with prominent eosinophilic infiltrates were more common and included pancreatic allograft rejection (14 cases), LPSP (5 of 24 total LPSP cases evaluated), inflammatory myofibroblastic tumor (4 cases), and systemic mastocytosis (1 case). Patients with eosinophilic pancreatitis showed two distinct histologic patterns: 1) a diffuse periductal, acinar, and septal eosinophilic infiltrate with eosinophilic phlebitis and arteritis; and 2) localized intense eosinophilic infiltrates associated with pseudocyst formation. All three patients with eosinophilic pancreatitis had peripheral eosinophilia, and all had multiorgan involvement. One patient with LPSP also had marked peripheral eosinophilia, and 5 of 24 LPSP cases demonstrated prominent eosinophilic infiltrates in the gallbladder, biliary tree, and/or duodenum. Notably, not all of these patients with LPSP with prominent eosinophils in other organs had increased eosinophils in the pancreas itself. These results emphasize the infrequent nature of pancreatic eosinophilia and its multiple potential disease associations. True eosinophilic pancreatitis, although a fascinating clinicopathologic entity, is one of the rarest causes of pancreatic eosinophilia.

Adult↗

Lymphoplasmacytic chronic cholecystitis and biliary tract disease in patients with lymphoplasmacytic sclerosing pancreatitis.

Lymphoplasmacytic sclerosing pancreatitis (LPSP) represents a distinctive form of chronic pancreatitis characterized by diffuse fibroinflammatory infiltrates that can involve both the pancreatic ducts and acinar parenchyma. Several cases of inflammatory infiltrates within the gallbladder have been reported in association with LPSP, but the spectrum of gallbladder pathology in patients with LPSP has not been systematically reviewed. Many patients with LPSP have distal CBD fibrosis, strictures, and inflammation, features that overlap somewhat with primary sclerosing cholangitis (PSC). In PSC, a pattern of gallbladder pathology termed "diffuse acalculous lymphoplasmacytic chronic cholecystitis" has been previously described as showing a triad of diffuse, mucosal-based, plasma cell-rich inflammatory infiltrates. We studied 20 gallbladders from patients with LPSP and compared them with 20 gallbladders in PSC, 20 gallbladders with chronic cholelithiasis, and 10 gallbladders from patients with benign (non-LPSP) pancreatic disease. The following features were evaluated: degree and composition of mucosal inflammation and deep (mural) inflammation, lymphoid nodules, metaplasia, dysplasia/neoplasia, fibrosis, muscular hypertrophy, Rokitansky-Aschoff sinuses, and cholesterolosis. The majority (60%) of gallbladders in LPSP contained moderate or marked inflammatory infiltrates and lymphoid nodules, frequencies similar to PSC but significantly higher than in chronic cholelithiasis and benign non-LPSP pancreatic disease. LPSP gallbladders received the highest scores for deep inflammation of all groups, and 35% of LPSP gallbladders showed transmural chronic cholecystitis. Overall, "diffuse lymphoplasmacytic chronic cholecystitis" was present in 50% of PSC cases and 25% of LPSP cases, but in only 5% of chronic cholelithiasis and none of non-LPSP benign pancreatic disease. Mucosal inflammation in LPSP gallbladders correlated significantly with the presence of inflammation in the extrapancreatic portion of the CBD. These findings suggest that inflammatory pathology of the gallbladder is frequently associated with LPSP and that it is part of the spectrum of biliary tract disease in these patients, rather than a simple reflection of the pancreatitis itself.

Adolescent↗

Pathogenesis of colloid (pure mucinous) carcinoma of exocrine organs: Coupling of gel-forming mucin (MUC2) production with altered cell polarity and abnormal cell-stroma interaction may be the key factor in the morphogenesis and indolent behavior of colloid carcinoma in the breast and pancreas.

In the exocrine organs, breast and pancreas, colloid carcinoma (CC, pure mucinous carcinoma), characterized by well-circumscribed lakes of mucin that contain scanty, detached malignant cells, has a significantly better prognosis than conventional ductal carcinomas (DCs). It has been speculated by us and others that an inverse polarization of cells may be responsible for the accumulation of extracellular mucin. Another possibility is that this mucin is biochemically and biologically distinct from the mucin secreted by the conventional carcinomas of these organs. This study was undertaken to investigate these two hypotheses: 1) To test whether there is indeed an alteration in cell polarity in CC. Immunohistochemical stains for luminal surface glycoproteins (carcinoembryonic antigen in pancreas and MUC1 in breast) were performed in 18 pancreatic and 30 mammary CCs and compared with the expression pattern in DCs (37 pancreatic and 47 mammary) and normal ducts. The results disclosed that these glycoproteins were expressed predominantly in the stroma-facing surfaces of CC cells, in contrast to the DCs, in which the expression was either on the luminal surface (in well-differentiated areas) or dispersed throughout the cell, intracytoplasmic in the poorly differentiated areas. Ultrastructural examination performed on 10 breast and two pancreatic CCs showed the condensation of mucigen granules (generally underlying an apical-type cell membrane) in the stroma-facing surface in all cases. In contrast, in the DCs (five pancreatic and five mammary), no clustering of mucigen granules was identified in the cytoplasm facing the stroma in any of the cases. Furthermore, no external lamina or basement membrane was detected in any of the CCs, whereas in the DCs, a distinct (in 3 of 10) or discontinuous (4 of 10) external lamina separated the tumor cells from the stroma. 2) To determine the expression frequency of MUC2 in CCs and to compare it with that in DCs and normal tissue, immunohistochemical stains with MUC2 (clone ccp58) were performed. MUC2 expression was detected in 18 of 18 pancreatic and 30 of 30 breast CCs and was exceedingly rare in DCs (1 of 136 pancreatic DC and 3 of 47 mammary, p <0.0001 in both organs). No labeling was detected in normal ducts. In conclusion, it appears that coupling of two factors is important for the distinctive morphologic characteristics and slow growth of CCs: The first one is the alteration in cell orientation as evidenced by the direction of surface glycoproteins and secretory organelles to the stroma-facing surface of the cells and the disruption of cell-stroma interaction as manifested by lack of basal lamina formation. Apparently, this altered polarity allows the CC cells to secrete the mucin toward the stroma. The mucin produced, MUC2 (also called gel-forming mucin), is highly specific for CC and is known to form strong bonds with the stroma, and also was found recently to have tumor suppressor activity. This distinctive mucin, accumulated in the stroma surrounding the CC cells, may act as a containing factor, slackening the spread of the cells.

Adenocarcinoma, Mucinous↗

Gene expression in neoplasms of the pancreas: applications to diagnostic pathology.

It seems that, lately, every pathology journal has three or four articles documenting the discovery of another genetic alteration or describing global gene expression in a series of cancers. Although these discoveries provide insight into the biology of neoplasia, it is less clear how they can be quickly and efficiently translated to patient care. This review will use neoplasms of the pancreas as a model and show how recent discoveries of genetic alterations and gene expression patterns can have a significant impact on the diagnosis and even treatment of tumors. Emphasis will be placed on applications that are practical and useful to the daily practice of pathology.

Biomarkers, Tumor↗