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In this study, the effect of heterozygous germline mutations in the heparan sulfate (HS) glycosaminoglycan chain co-polymerases EXT1 and EXT2 on glomerular barrier function and the endothelial glycocalyx in humans is investigated. Heparan sulfate (HS) glycosaminoglycans are deemed essential to the glomerular filtration barrier, including the glomerular endothelial glycocalyx. Animal studies have shown that loss of HS results in a thinner glycocalyx. Also, decreased glomerular HS expression is observed in various proteinuric renal diseases in humans. A case report of a patient with an EXT1 mutation indicated that this could result in a specific renal phenotype. This patient suffered from multiple osteochondromas, an autosomal dominant disease caused by mono-allelic germline mutations in the EXT1 or EXT2 gene. These studies imply that HS is indeed essential to the glomerular filtration barrier. However, loss of HS did not lead to proteinuria in various animal models. We demonstrate that multiple osteochondroma patients do not have more microalbuminuria or altered glycocalyx properties compared to age-matched controls (n = 19). A search for all Dutch patients registered with both osteochondroma and kidney biopsy (n = 39) showed that an EXT1 or EXT2 mutation does not necessarily lead to specific glomerular morphological phenotypic changes. In conclusion, this study shows that a heterozygous mutation in the HS backbone elongating enzymes EXT1 and EXT2 in humans does not result in (micro)albuminuria, a specific renal phenotype or changes to the endothelial glycocalyx, adding to the growing knowledge on the role of EXT1 and EXT2 genes in pathophysiology.

OBJECTIVE: To provide an embryological explanation for the presence of ovarian stroma in cystadenomas of the liver and pancreas. DESIGN: Investigation of patients and embryos. METHOD: From 1997 to 2001 in the Academic Medical Centre, Amsterdam, the Netherlands, nine women were treated for a cystadenoma with ovarian stroma, six of which were situated in the liver and three in the tail of pancreas. In one patient with a cystadenoma in the liver, malignant changes had taken place. In embryos at 5-8 weeks development, the regional differences in the morphology of the epithelium of the peritoneal cavity and the position of the gonads in relation to the embryonic liver, pancreas and spleen were examined. RESULTS: In the foetal period before the gonads begin to descend, they are situated directly dorsal to the liver, tail of pancreas and spleen, but are separated from these by the peritoneal cavity. The cells that cover the urogenital folds distinguish themselves from those elsewhere in the peritoneal cavity as they are bulging in shape as opposed to flattened. This activated morphology suggests that on physical contact with a neighbouring organ the cells covering the gonads may become detached and lodge in that organ. CONCLUSION: It is likely that cystadenomas of the liver and pancreas have their origin in the cells that cover the embryonic gonads. The anomalous morphology of these covering cells in fact suggests that they are relatively easily mobilized. They are probably comparable with inoculation metastasis in the coelomic cavity. Taking the chance of malignant transformation of a cystadenoma into account, the treatment of choice is radical resection of the abnormality.

Sulindac causes the reduction of adenomas in familial adenomatous polyposis (FAP) patients, but complete regression is unusual, and breakthrough of colorectal carcinoma during sulindac treatment has been described. The molecular features related to sulindac resistance are unknown. Therefore, we investigated molecular alterations in adenomas from FAP patients with complete adenoma regression on sulindac (responsive patients) and from FAP patients with sulindac-resistant adenomas (resistant patients). Fourteen baseline adenomas (removed before sulindac treatment) from six responsive patients were studied. Also, 9 baseline adenomas and 34 resistant adenomas (removed during sulindac treatment) from three resistant patients were analyzed. Using immunohistochemistry, we evaluated the expression of beta-catenin, cyclooxygenase-2 (Cox-2), p53, Bcl-2, and Bax. K-ras codon 12 mutations, loss of heterozygosity at 5q (APC locus), and microsatellite instability were studied with PCR-based techniques. There were no significant differences between baseline adenomas from sulindac-responsive and -resistant patients (P > 0.05). There was less loss of membranous beta-catenin staining and less nuclear beta-catenin accumulation in resistant adenomas compared with baseline adenomas from the same (sulindac-resistant) patients (P < 0.01) or baseline adenomas from responsive patients (P < 0.01). Epithelial Cox-2 expression was less, though not significant, in resistant adenomas compared with baseline adenomas from resistant patients, but was significantly less in baseline adenomas from responsive patients (P < 0.01). K-ras mutations were found in 8 of 34 resistant adenomas (24%) and in none of the baseline adenomas (P < 0.05). Stromal Cox-2 expression, staining of p53 and Bcl-2, and loss of heterozygosity at 5q were comparable in both groups. Loss of Bax staining and microsatellite instability were not found in any adenoma. Sulindac-resistant adenomas display less alteration in beta-catenin staining and less epithelial Cox-2 expression when compared with adenomas removed before sulindac treatment. K-ras mutations may contribute to sulindac-resistance. Continued research is needed to investigate molecular alterations related to sulindac resistance

Sebaceous gland carcinomas (SGCs) are rare malignant skin tumors occurring sporadically or as a phenotypic feature of the Muir-Torre syndrome (MTS). A subset of patients with MTS have a variant of the hereditary nonpolyposis colorectal cancer syndrome caused by mutations in mismatch repair (MMR) genes, which lead to microsatellite instability (MSI). We evaluated the value of MSI and loss of expression of the MMR genes, hMLH-1 and hMSH-2, as a marker to identify and distinguish MTS from sporadic SGC. Using a nationwide pathology report database system, we identified patients with the MTS phenotype. SGCs from 10 MTS patients and the colorectal carcinomas from 3 additional MTS patients were collected. In addition, SGCs from eight patients without a history of visceral neoplasm were collected. MSI was detected in 9 of 13 MTS-associated tumors (69%) versus 0 of 8 sporadic SGCs (P = 0.002). Except for the age of onset of colorectal carcinoma [58 years in the MSI-positive group versus 69.8 years in the MSI-negative group (P = 0.17)], no differences were seen between the MSI-negative and the MSI-positive MTS patients. Loss of expression of hMLH-1 (n = 4) or hMSH-2 (n = 4) was found in MSI-positive patients only. MSI and loss of expression of MMR genes can be used as markers for MTS in patients with SGC. Consequently, MSI and loss of MMR gene expression in a patient presenting with SGC as the initial malignancy have important consequences for the patient and family. There are at least two variants of MTS with different molecular genetic mechanisms because 31% of the patients with the MTS phenotype had no MSI

Partial gastrectomy is a well-established pre-malignant condition. It is postulated that in the gastric stump an accelerated neoplastic process takes place, similar to that of (intestinal type) adenocarcinoma from the non-operated stomach. K-ras codon 12 mutation is one of the most frequent oncogenic alterations in human solid neoplasms. It is rare in conventional gastric carcinoma and has not been studied in gastric stump carcinoma. The aim of this study was to compare the prevalence of K-ras codon 12 point mutations in gastric stump carcinomas with those in conventional carcinomas from the non-operated stomach. Twenty-four gastric stump carcinomas were compared with 26 conventional gastric carcinomas. Stage, histology, and demographics were comparable in both groups. Mutations in codon 12 of the K-ras gene were examined with a polymerase chain reaction (PCR)-based method and subsequent dot blot hybridization with mutation-specific probes. The results of Helicobacter pylori infection, Epstein-Barr virus infection and p53 immunohistochemistry were partially known from a previous study. In one of the gastric stump carcinomas as well as in one of the conventional gastric carcinomas a K-ras codon 12 point mutation was found. p53 immunohistochemistry results were comparable in both groups. Interestingly, Helicobacter pylori infection rate and Epstein-Barr virus in situ hybridization for EBER1, as previously studied, appeared were significantly different in the two groups. K-ras codon 12 point mutations are rare in both gastric stump carcinomas and conventional gastric carcinomas. This supports the postulated hypothesis that the pathways of carcinogenesis in both gastric stump carcinoma and conventional gastric carcinoma share common features. However, these groups differ in infection rate of Helicobacter pylori and of Epstein-Barr virus, which suggests that some neoplastic stimuli differ as well

In normal lymphoid tissues the tumour necrosis factor-receptor family member CD27 and its ligand CD70 have a restricted expression pattern. Previously, we reported that expression of CD27 is deregulated in B-cell leukaemias and lymphomas. Here we show that, although infrequently expressed by normal human B cells in vivo, CD70 is found on 50% of B-CLLs, 33% of follicle centre lymphomas, 71% of large B-cell lymphomas, and 25% of mantle cell lymphomas. Interestingly, in the majority of leukaemias and lymphomas examined, CD70 was found to have a capped appearance, a feature that coincided with co-expression of CD27. Functional analysis showed that a subset of B-CLLs could proliferate vigorously in response to CD70 mAb but not to CD27 mAb. This response was synergistically enhanced by ligation of CD40 but inhibited by the presence of IL-4. Additional experiments indicated that the proliferative response was due to an agonistic signal delivered via CD70, rather than blocking of negative signalling by CD27. Thus, next to its role as ligand, in a subset of malignant B cells CD70 can operate as receptor and as such might contribute to progression of these B-cell malignancies

Most non-Hodgkin's lymphomas (NHLs) express a number of different adhesion receptors. A large body of evidence indicates that these adhesion receptors not only regulate normal lymphocyte trafficking but also play a pivotal role in the dissemination of NHL. Thus, cutaneous lymphocyte antigen, alpha 4 beta 7, alpha E beta 7, and L-selectin, which mediate the tissue-specific positioning of normal lymphocytes in the skin, mucosa, epithelium and lymph nodes, respectively, are selectively expressed on lymphomas localized at these sites. Furthermore, expression of CD44, a family of adhesion receptors with pleiotropic effects on tumor behavior, is related to lymphoma aggressiveness and dissemination. Taken together, these findings offer a framework for the understanding of tumor dissemination in NHL. In view of the similarities between lymphocyte behavior and the metastatic behavior of solid tumors, these insights might contribute to the understanding of the basic mechanisms underlying tumor metastasis in non-lymphoid tumors

Recent studies have identified the integrin alpha 4 beta 7 as a mucosal homing receptor that mediates lymphocyte migration to the intestinal mucosa by binding to MAdCAM-1, a vascular recognition molecule (addressin) selectively expressed on mucosal endothelium. In the present study, we have assessed the expression of alpha 4 beta 7 on B- and T-cell non-Hodgkin's lymphomas of different primary localization and on related normal lymphocytes. Among B-lineage lymphomas, expression of alpha 4 beta 7 was present in the majority of cases of malignant lymphomatous polyposis of the intestine and low-grade lymphoma of the mucosa-associated lymphoid tissue/monocytoid B-cell lymphoma and in some cases of precursor B-cell lymphoma. CLL/small lymphocytic lymphoma, (nodal) mantle cell lymphoma, follicular center cell lymphoma, Burkitt's lymphoma, and diffuse large B-cell lymphoma were virtually always alpha 4 beta 7 negative, as was the case when localized in the mucosa-associated lymphoid tissue. The normal B cells of the follicle mantles and part of the B cells of the extrafollicular B-cell compartment of lymphoid tissues expressed moderate levels of alpha 4 beta 7. By contrast, follicular center cells were alpha 4 beta 7 negative. Among T-lineage lymphomas, expression of alpha 4 beta 7 was also strongly related to the primary localization; in mucosal, nodal, and cutaneous T cell lymphomas the percentage of positive cases was 56%, 17%, and 0%, respectively. All cases of precursor T-cell lymphoma were alpha 4 beta 7 negative. High expression of alpha 4 beta 7 was found on a subset of peripheral blood memory T cells as well as on lymphocytes in the intestinal mucosa. We conclude that non-Hodgkin's lymphomas that are related to mucosa-associated B- and T-lymphocyte populations selectively express the mucosal homing receptor alpha 4 beta 7. The presence of this receptor underscores their distinctive character and may play an important role in determining their characteristic mucosal dissemination pattern