Tracing the origin of a metastasis of a neuroendocrine carcinoma is a challenge. The transcription factors Cdx2 and TTF1 have been found to be helpful in identifying well-differentiated ...neuroendocrine tumors of gastrointestinal and pulmonary origin, respectively. So far, such a marker is lacking for pancreatic neuroendocrine tumors (PETs) and metastases thereof. Islet1 (Isl1) is a transcription factor expressed in pancreatic islet cells. The aim of this study was (1) to test the specificity and sensitivity of Isl1 as a marker of PETs, and (2) to test the specificity and sensitivity of a panel of markers, including Isl1, Cdx2, and TTF1, for the localization of the primary.
One hundred eighty-eight primary gastroenteropancreatic and pulmonary endocrine tumors and 49 metastases thereof were examined. Immunohistochemistry using antibodies directed against Isl1, Cdx2, and TTF1 was performed and the staining results were scored semiquantitatively.
Isl1 proved to be a highly specific marker for pancreatic endocrine tumors. In 84 primary PET its specificity was 78.4% (sensitivity 74.3%) and in 18 metastases of PET the specificity reached 100% (sensitivity 77.8%). Strong Cdx2 staining showed a specificity for gastrointestinal origin of 83.9% (sensitivity 82%) in primary tumors and of 100% (sensitivity 40%) in metastases. Including weakly positive tumors lead to a decreased specificity but an increased sensitivity. TTF1 expression was detected in 2 PET and 1 ileal primary tumor only and was absent in all metastases of gastroenteropancreatic endocrine tumors.
Isl1 is a reliable marker of pancreatic endocrine tumors and metastases thereof. It shows a comparable sensitivity and specificity as Cdx2 as a marker of ileal and appendiceal neuroendocrine tumors and their metastases. TTF1 is very rarely expressed in well-differentiated gastroentero-PETs. Therefore, the panel of Isl1, Cdx2, and TTF1 seems useful for examining metastases of well-differentiated endocrine carcinomas of unknown origin.
The differential pathophysiologic mechanisms that trigger and maintain the two forms of inflammatory bowel disease (IBD), Crohn disease (CD), and ulcerative colitis (UC) are only partially ...understood. cDNA microarrays can be used to decipher gene regulation events at a genome-wide level and to identify novel unknown genes that might be involved in perpetuating inflammatory disease progression.
High-density cDNA microarrays representing 33,792 UniGene clusters were prepared. Biopsies were taken from the sigmoid colon of normal controls (n = 11), CD patients (n = 10) and UC patients (n = 10). 33P-radiolabeled cDNA from purified poly(A)+ RNA extracted from biopsies (unpooled) was hybridized to the arrays. We identified 500 and 272 transcripts differentially regulated in CD and UC, respectively. Interesting hits were independently verified by real-time PCR in a second sample of 100 individuals, and immunohistochemistry was used for exemplary localization. The main findings point to novel molecules important in abnormal immune regulation and the highly disturbed cell biology of colonic epithelial cells in IBD pathogenesis, e.g., CYLD (cylindromatosis, turban tumor syndrome) and CDH11 (cadherin 11, type 2). By the nature of the array setup, many of the genes identified were to our knowledge previously uncharacterized, and prediction of the putative function of a subsection of these genes indicate that some could be involved in early events in disease pathophysiology.
A comprehensive set of candidate genes not previously associated with IBD was revealed, which underlines the polygenic and complex nature of the disease. It points out substantial differences in pathophysiology between CD and UC. The multiple unknown genes identified may stimulate new research in the fields of barrier mechanisms and cell signalling in the context of IBD, and ultimately new therapeutic approaches.
1 First Department of Medicine, Christian-Albrechts-University Kiel, D-24105 Kiel, Germany
2 AstraZeneca R&D Mölndal, S-43183 Mölndal, Sweden
3 Department of Pathology, Christian-Albrechts-University ...Kiel, D-24105 Kiel, Germany
4 Max-Planck Institute for Molecular Genetics, D-14195 Berlin, Germany
Large-scale public data mining will become more common as public release of microarray data sets becomes a corequisite for publication. Therefore, there is an urgent need to clarify whether data from different microarray platforms are comparable. To assess the compatibility of microarray data, results were compared from the two main types of high-throughput microarray expression technologies, namely, an oligonucleotide-based and a cDNA-based platform, using RNA obtained from complex tissue (human colonic mucosa) of five individuals. From 715 sequence-verified genes represented on both platforms, 64% of the genes matched in "present" or "absent" calls made by both platforms. Calls were influenced by spurious signals caused by Alu repeats in cDNA clones, clone annotation errors, or matched probes that were designed to different regions of the gene; however, these factors could not completely account for the level of call discordance observed. Expression levels in sequence-verified, platform-overlapping genes were not related, as demonstrated by weakly positive rank order correlation. This study demonstrates that there is only moderate overlap in the results from the two array systems. This fact should be carefully considered when performing large-scale analyses on data originating from different microarray platforms.
noncommercial clone-based microarray system; commercial oligonucleotide-based microarray system; expression screening platform; cross-platform screening
S100P is a member of the S100 family of calcium-binding proteins and there have been several recent reports of its overexpression in pancreatic ductal adenocarcinoma (PDAC). We have used Far Western ...screening and
in vitro
interaction assays to identify and confirm a novel target protein for S100P. We have named this protein S100PBPR, and shown that its interaction with S100P is dependent on Ca
2+ or Mg
2+. S100PBPR was found to localize to cell nuclei where S100P is also present, and the two proteins co-immunoprecipitate. By
in situ
hybridization, S100PBPR transcript was found in islet cells but not duct cells of the healthy pancreas. Both S100P and S100PBPR were detected by quantitative real-time polymerase chain reaction in pancreatic intraepithelial neoplasia (PanIN) and PDAC samples, and
in situ
hybridization revealed the presence of S100PBPR transcript in malignant PDAC cells. These data suggest that an interaction between S100P and S100PBPR may be involved in early pancreatic cancer. S100P was further investigated in PanIN lesions and immunohistochemical analysis showed its expression to correlate significantly with increasing grade of PanINs, being found as early as PanIN-1 with more prevalent expression in PanIN-2 and -3. These data suggest that S100P can be added to the genetic progression model for PDAC.
This study examines the effects of chronically elevated glucose levels on the survival and function of purified rat beta-cells. Prolonged exposure (9 days) of beta-cell aggregates to 20 mmol/l ...glucose did not lead to cell losses, but reduced the amount of insulin secreted in response to glucose. This decrease was not caused by cellular desensitization but resulted from the lower cellular insulin content after a prolonged imbalance between stimulated rates of insulin synthesis and release. Virtually all beta-cells exhibited a state of metabolic and biosynthetic activation, which was maintained for at least 2 h in glucose-depleted media. Their rates of protein and insulin synthesis were amplified by glucose, reaching (half-) maximal stimulation at lower glucose concentrations (2 and 5 mmol/l, respectively) than control cells cultured at 10 mmol/l glucose (5 and 10 mmol/l, respectively). As for insulin release, the net glucose effect on insulin synthesis was markedly reduced as compared with that in control cells. This was also the case after culture at 6 mmol/l glucose. In the latter condition, the lower glucose-inducible activities were caused by cellular desensitization, with 50% of the beta-cells unresponsive to glucose and the other 50% responding with a lower sensitivity (half-maximal stimulation at 7 mmol/l glucose). Comparison of beta-cells cultured at the three glucose concentrations indicated that prolonged exposure to elevated glucose levels increases the number of degranulated cells, of cells with a high proportion of immature insulin granules, and of cells with glycogen deposition-morphologic features previously described in conditions of hyperglycemia. It is concluded that chronic exposure (9 days) of rat beta-cells to elevated glucose levels induces a prolonged state of beta-cell activation and glucose hypersensitivity rather than a glucotoxicity or glucose desensitization. This shift in the functional state of the beta-cell population is responsible for a reduced insulin release in response to glucose, as observed in other conditions of prolonged exposure to high glucose levels.
Allelotype of pancreatic acinar cell carcinoma Rigaud, Gildas; Moore, Patrick S.; Zamboni, Giuseppe ...
International journal of cancer,
1 December 2000, Letnik:
88, Številka:
5
Journal Article
: Transgenic mice overexpressing transforming growth factor‐α (TGF‐α) display an expansion of intrapancreatic fibroblasts and a progressive accumulation of extracellular matrix. This massive fibrosis ...is associated with an increase in pancreatic size and weight. In parallel, tubular complexes appear that are composed of acinar cells with a decreased height. These acinar cells lose zymogen granules and become transitional cells, which subsequently gain duct cell features. In animals older than one year dysplastic lesions develop, which originate from tubular complexes. Occasionally these dysplastic foci transform to papillary and cystic pancreatic carcinoma. These tumors are positive for the duct‐specific antigen Duct‐1 and carbonic anhydrase activity indicative of ductal differentiation. Tumors overexpress the epidermal growth factor (EGF)‐receptor and p53, but lack K‐ras mutations. These data suggest an acinar‐ductal‐carcinoma sequence in TGF‐α transgenic mice.
Pancreatoblastoma in childhood is a very rare malignant tumor, but is considered to have a relatively good prognosis because of its low metastatic potential. We report 1-day-old female infant who was ...recently found to have an intraabdominal cyst on prenatal ultrasound examination. The tumor was a unilocular, cystic mass without invasion or metastasis to other organs, allowing total resection. It was diagnosed postnatally with pancreatoblastoma.
Background & Aims: In transgenic mice overexpressing transforming growth factor (TGF)-α in the exocrine pancreas, progressive pancreatic fibrosis and a transdifferentiation of acinar cells to ...duct-like cells occurs. The present study was undertaken to analyze this transdifferentiation process.
Methods: Pancreatic specimens were characterized using light microscopy and immunohistochemistry. Expression of the epidermal growth factor receptor (EGFR) and TGF-α was evaluated with slot blot and Western analysis. To identify other generic events, K-
ras mutations were screened with an enriched polymerase chain reaction approach and p53 expression was detected with immunohistochemistry.
Results: Morphological examination revealed an aggregation of interlobular fibroblasts and a decrease in acinar cell height starting at day 14 after birth. In older animals, these acinar cells change to duct-like cells, which form tubular structures and express ductal markers. Evidence for dysplastic changes was found in 12 of 21 TGF-α transgenic mice older than 1 year. We also observed four malignant pancreatic tumors, which were multicentric and originated from dysplastic tubular complexes. They displayed a mixed cystic-papillary phenotype strongly positive for carbonic anhydrase activity. EGFR expression progressively increased in the transition from acinar to duct-like and transformed cells. Activating K-
ras mutations could not be detected; however, tubular complexes and tumors displayed increased immunoreactivity for nuclear p53.
Conclusions: These data suggest an involvement of the TGF-α/EGFR pathway in conjunction with other yet unknown events in pancreatic tumor development. Furthermore, these observations are in favor of an acinar-ductal carcinoma sequence. Thus, these transgenic animals will be useful to define genetic alterations associated with a transition from acinar cells to a neoplastic ductal phenotype.
GASTROENTEROLOGY 1998;115:1254-1262
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