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Fibroblast specific protein 1 (FSP1/S100A4) is an intracellular calcium binding protein which has been linked to epithelial-mesenchymal transition, tissue fibrosis, pulmonary vascular disease, metastatic tumour development, increased tumour cell motility and invasiveness. This protein is reported to be uniquely expressed in newly formed and differentiated fibroblasts and has been used in various studies to demonstrate epithelial-mesenchymal transition (EMT). However, S100A4 immunoreactivity does not solely fit the distribution and shape of fibroblasts; therefore, we aimed to characterize S100A4 positive cells in different human tissue compartments. We found S100A4 expression in a wide range of cells, including cells of haematopoietic lineage, namely CD4 and CD8 positive T-lymphocytes, but not B-lymphocytes. All investigated monocytes, macrophages and specialised histiocytes were positive for S100A4. Only a limited number of fibroblasts and most smooth muscle actin positive myofibroblasts expressed S100A4. Even some epithelial cells of the kidney and bladder were positive for S100A4. Expression was also found in the vasculature. Here, cells of the subendothelial space, tunica adventitia and some smooth muscle cells of the tunica media were positive for S100A4. Expression was also detected in the stroma of the prostate, adipocytes and in skeletal muscle. In summary, S100A4 is expressed in various cell types of different lineage. It is therefore not possible to equate the expression of this protein to fibroblasts. Hence, studies that used this marker as evidence of transition from epithelia to fibroblasts must be revisited.

Highlights • SalvGlandDx includes 27 genes known to be involved in salivary gland neoplasms • Can be applied to FFPE histological and cytological (cell block) specimen • Solely RNA extraction is needed • Gene fusions, hotspot mutations and gene expression levels can be detected • Guides diagnosis in uncertain cases and can detect therapeutically relevant fusions, Diagnosis of salivary gland neoplasms is often challenging due to their high morphological diversity and overlaps. Several recurrent molecular alterations have been described recently, which can serve as powerful diagnostic tools and potential therapeutic targets (e.g. NTRK or RET fusions). However, current sequential molecular testing can be expensive and time consuming. In order to facilitate the diagnosis of salivary gland neoplasms, we designed an all-in-one RNA-based next generation sequencing panel suitable for the detection of mutations, fusions and gene expression levels (including NR4A3) of 27 genes involved in salivary gland neoplasms. Here we present the validation of the “SalvGlandDx” panel on FFPE histological specimen including fine needle aspiration (FNA) cell block material, against the standard methods currently used at our institution. In a second part we describe selected unique cases in which the SalvGlandDx panel allowed proper diagnosis and new insights into special molecular characteristics of selected salivary gland tumors. We characterize a unique salivary gland adenocarcinoma harboring a ZCCHC7-NTRK2 fusion, a highly uncommon spindle cell and pseudoangiomatoid adenoid-cystic carcinoma with MYBL1-NFIB fusion, and a purely oncocytic mucoepidermoid carcinoma, whereas diagnosis could be made by detection of a CRTC3-MAML2 rearrangement on the cell block specimen of the FNA. Further, a rare case of a SS18-ZBTB7A rearranged low-grade adenocarcinoma previously described as potential spectrum of microsecretory adenocarcinoma, is reported. In addition, features of six cases within the spectrum of polymorphous adenocarcinoma / cribriform adenocarcinoma of salivary gland including PRKD1 p.E710D mutations and novel fusions involving PRKAR2A-PRKD1, SNX9-PRKD1 and ATL2-PRKD3, are described.

Worldwide, various autopsy studies have shown a decrease in the diagnostic error rate over the last years. The cause of this positive development is mainly due to the improvement of modern medicine. However, intensive care unit patients are thought to have a higher risk for diagnostic errors, which is documented in several studies in the adult population. In contrast, there is only limited information about diagnostic errors in pediatrics, particularly in pediatric and neonatal intensive care units. The aims of this study were to analyze the spectrum of childhood death, determine the prevalence and distribution of autopsy-confirmed diagnostic errors, and describe patient characteristics that might have influenced the discordance between antemortem and postmortem findings. We analyzed 143 autopsy reports from 2004 to 2013 and correlated these with clinical reports. The overall autopsy rate during this interval was 20.3%. The leading causes of death were congenital malformations (28%), diseases closely associated with perinatal disorders (25%), disorders of the cardiovascular system (18%), and infections (15%). Additional findings were obtained in 23% of the autopsies. Major diagnostic errors were found in 6%, the lowest reported value in a developed country as yet. Most cases (75%) showed complete concordance between clinical diagnoses and postmortem findings, in line with improvements in diagnostic and therapeutic processes over the last decades. In conclusion, autopsy of neonates, infants, and children represents an important tool for monitoring the quality of pediatric and neonatal medical care.

Zusammenfassung: Wir beschreiben einen testikulären primitiven neuroektodermalen Tumor (PNET) mit intratubulärer Keimzellneoplasie des angrenzenden Hodenparenchyms bei einem 25-jährigen Patienten. Testikuläre PNET sind selten. Ihre Entstehung wird auf eine maligne somatische Transformation in einem testikulären Keimzelltumor zurückgeführt. Morphologisch und molekularpathologisch ähneln diese Tumoren kindlichen zentralen PNET, die keine Rearrangierung des EWS-Gens auf Chromosom22 aufweisen. Auch im hier beschriebenen Fall konnte keine Translokation nachgewiesen werden

Regulation of cytotoxic effector molecule expression in human CTLs after viral or bacterial activation is poorly understood. By using human autologous dendritic cells (DCs) to prime T lymphocytes, we found perforin only highly up-regulated in virus- (HSV-1, vaccinia virus) but not in intracellular bacteria- (Listeria innocua, Listeria monocytogenes, Mycobacterium tuberculosis, Chlamydophila pneumoniae) activated CTLs. In contrast, larger quantities of IFN-γ and TNF-α were produced in Listeria-stimulated cultures. Granzyme B and granulysin were similarly up-regulated by all tested viruses and intracellular bacteria. DCs infected with HSV-1 showed enhanced surface expression of the costimulatory molecule CD252 (CD134L) compared with Listeria-infected DC and induced enhanced secretion of IL-2. Adding blocking CD134 or neutralizing IL-2 Abs during T cell activation reduced the HSV-dependent up-regulation of perforin. These data indicate a distinct CTL effector function in response to intracellular pathogens triggered via differing endogenous IL-2 production upon costimulation through CD252.

OBJECTIVES: Smoking increases the risk of developing rheumatoid arthritis (RA) and worsens the course of the disease. In the current study we analysed whether smoking can affect gene expression directly in the joints. METHODS: Synovial fibroblasts were incubated with 5 cigarette smoke extract and changes in gene expression were detected using whole genome microarrays and verified with real time PCR. Synovial tissues were obtained from smoking and non smoking patients with RA undergoing joint replacement surgery and from mice exposed to cigarette smoke or ambient air in a whole body exposure chamber for 3 weeks. RESULTS: Microarray and real time PCR analysis showed a significant upregulation of the heat shock proteins DnaJA4 DnaJB4 DnaJC6 HspB8 and Hsp70 after stimulation of synovial fibroblasts with 5 cigarette smoke extract. Similarly in synovial tissues of smokers with RA the expression of DnaJB4 DnaJC6 HspB8 and Hsp70 was significantly higher compared with non smokers with RA. Upregulation of DnaJB4 and DnaJC6 in joints by smoking was also confirmed in mice exposed to cigarette smoke. CONCLUSIONS: Our data clearly show that smoking can change gene expression in the joints which can lead to the activation of signalling pathways that promote development of autoimmunity and chronic joint inflammation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights licensing/permissions.

Objective:The most difficult thyroid tumors to be diagnosed by cytology and histology are conventional follicular carcinomas (cFTCs) and oncocytic follicular carcinomas (oFTCs). Several microRNAs (miRNAs) have been previously found to be consistently deregulated in papillary thyroid carcinomas; however, very limited information is available for cFTC and oFTC. The aim of this study was to explore miRNA deregulation and find candidate miRNA markers for follicular carcinomas that can be used diagnostically.Design:Thirty-eight follicular thyroid carcinomas (21 cFTCs, 17 oFTCs) and 10 normal thyroid tissue samples were studied for expression of 381 miRNAs using human microarray assays. Expression of deregulated miRNAs was confirmed by individual RT-PCR assays in all samples. In addition, 11 follicular adenomas, two hyperplastic nodules (HNs), and 19 fine-needle aspiration samples were studied for expression of novel miRNA markers detected in this study.Results:The unsupervised hierarchical clustering analysis demonstrated individual clusters for cFTC and oFTC, indicating the difference in miRNA expression between these tumor types. Both cFTCs and oFTCs showed an up-regulation of miR-182/-183/-221/-222/-125a-3p and a down-regulation of miR-542-5p/-574-3p/-455/-199a. Novel miRNA (miR-885-5p) was found to be strongly up-regulated (>40-fold) in oFTCs but not in cFTCs, follicular adenomas, and HNs. The classification and regression tree algorithm applied to fine-needle aspiration samples demonstrated that three dysregulated miRNAs (miR-885-5p/-221/-574-3p) allowed distinguishing follicular thyroid carcinomas from benign HNs with high accuracy.Conclusions:In this study we demonstrate that different histopathological types of follicular thyroid carcinomas have distinct miRNA expression profiles. MiR-885-5p is highly up-regulated in oncocytic follicular carcinomas and may serve as a diagnostic marker for these tumors. A small set of deregulated miRNAs allows for an accurate discrimination between follicular carcinomas and hyperplastic nodules and can be used diagnostically in fine-needle aspiration biopsies.

The efficacy of mammalian target of rapamycin (mTOR) inhibitors is currently tested in patients affected by autosomal dominant polycystic kidney disease. Treatment with mTOR inhibitors has been associated with numerous side effects. However, the renal-specific effect of mTOR inhibitor treatment cessation in polycystic kidney disease is currently unknown. Therefore, we compared pulse and continuous everolimus treatment in Han:SPRD rats. Four-week-old male heterozygous polycystic and wild-type rats were administered everolimus or vehicle by gavage feeding for 5 wk, followed by 7 wk without treatment, or continuously for 12 wk. Cessation of everolimus did not result in the appearance of renal cysts up to 7 wk postwithdrawal despite the reemergence of S6 kinase activity coupled with an overall increase in cell proliferation. Pulse everolimus treatment resulted in striking noncystic renal parenchymal enlargement and glomerular hypertrophy that was not associated with compromised kidney function. Both treatment regimens ameliorated kidney function, preserved the glomerular-tubular connection, and reduced proteinuria. Pulse treatment at an early age delays cyst development but leads to striking glomerular and parenchymal hypertrophy. Our data might have an impact when long-term treatment using mTOR inhibitors in patients with autosomal dominant polycystic kidney disease is being considered.

Carcinomas of the Vaterian system are rare and presumably arise from preexisting adenomas (adenoma-carcinoma-sequence). Usually, biopsies are obtained to confirm and specify endoscopic findings, but differentiating reactive atypia from dysplasia or dysplasia from invasive carcinoma can sometimes be difficult or even impossible on morphological criteria alone. In case of invasive carcinoma, furthermore, the precise classification of carcinoma subtypes needs to be established since the distinct subtypes differ significantly in terms of clinical outcome. The cell adhesion proteins CD24, P-cadherin and S100A4 were shown to be expressed in several carcinomas and in dysplastic epithelium but only rarely in normal mucosa. We therefore investigated their expression in 177 carcinoma, 114 adenoma and 152 normal mucosa specimens of the ampulla of Vater. Although the expression of the cell adhesion proteins did not differ between the carcinoma subtypes, marked differences between normal mucosa, adenoma and carcinoma samples were observed. All marker proteins were expressed in less than 7% of normal mucosa samples (S100A4 in only 1% of cases) and showed an increasing expression from adenoma to invasive carcinoma. Our findings suggest that P-cadherin and S100A4 are helpful in discriminating normal mucosa or reactive atypia from neoplastic lesions. CD24 and S100A4, furthermore, can assist in the differential diagnosis of dysplasia vs invasive carcinoma.

During a study on the mTor pathway in the rat kidney we observed a striking increase of the phosphorylation of the S6 kinase in mitosis. In cryostat sections of perfusion-fixed tissue mitotic cells appeared as bright spots in immunofluorescence using an antibody specific for the phosphorylation site Thr421/Ser424. They were easily spotted in overviews with the objective 4x and 10x. Immunofluorescence was weak during the interphase. During the prophase it increased in both the nucleus and the cytoplasm and it remained bright during the subsequent phases of mitosis. All mitotic cells which were found in tubules and in the interstitium of the kidney using a chromatin stain displayed the bright immunofluorescence for phospho-S6 kinase. The same phenomenon was observed in rat liver and in mouse kidney as well as in a human cell line. Provided a rapid fixation, mitotic cells could be identified with the immunoperoxidase technique in paraffin sections of immersion-fixed tissue. This is the first report of phosphorylation of S6 kinase during mitosis in vivo. Thus, immunohistochemistry with anti-phospho-S6 kinase (Thr421/Ser424) appears to provide a convenient way to detect mitotic cells at low magnification.

SUMMARY: Aim: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by an imbalance between tubular epithelial cell proliferation and apoptosis. We have previously shown that the mammalian target of rapamycin (mTOR) signalling pathway is aberrantly activated in the cystic kidneys of Han:SPRD rats with ADPKD. Because the Akt kinase is an upstream regulator of mTOR, we hypothesized that the activity of Akt could be enhanced in the kidneys of Han:SPRD rats. Methods: Reverse transcription-polymerase chain reaction, western blot, enzyme-linked immunosorbent assay and immunohistochemistry were used to analyse Akt expression in rat polycystic kidneys. Results: Wild-type (+/+) and heterozygous (Cy/+) Han:SPRD rats showed constitutive expression of Akt-1, -2 and -3 mRNA by reverse transcription-polymerase chain reaction analysis with no significant difference between Cy/+ and +/+ kidneys. Western blotting and enzyme-linked immunosorbent assay showed a significant increase in phosphorylated Akt in Cy/+ compared with +/+ kidneys. The pattern of immunoreactivity for phosphorylated Akt in kidney sections was the same in +/+ and in Cy/+ rats, with very low levels in interphase cells, but extremely bright signals in mitotic cells, beginning with the onset of the prophase. The in vivo incorporation of bromo-deoxyuridine revealed approximately a ninefold higher rate of proliferation in Cy/+ cyst epithelia compared with normal tubule epithelia in +/+ rats, while the expression of the cell cycle marker Ki67 revealed approximately a sixfold higher rate of proliferation. In summary, enhanced phosphorylation of Akt can be demonstrated in Cy/+ kidneys which correlates with a markedly elevated proliferation rate of epithelial cells in cysts. Mitotic but not resting cells display strong phosphorylation of Akt. Conclusion: Because Akt is a proximal target of mTOR, its inhibition with specific antagonists could be useful to prevent or halt cystogenesis in ADPKD.

We searched for morphological evidence to support the hypothesis that stem cells are responsible for renal tubular cell proliferation. The rationale of the study was that if proliferation relies on progenitors, mitotically active cells should be less differentiated than their neighbors. As the retention of the thymidine analog BrdU has been the only approach employed to identify stem cells in the kidney up to now we additionally characterized BrdU-retaining cells. Rat kidneys were fixed by perfusion. Cycling cells identified by mitotic figures or the expression of the proliferating cell nuclear antigen (PCNA) were examined by light microscopy and electron microscopy as well as immunofluorescence for four differentiation markers. Newborn rats were injected with BrdU in order to detect label-retaining cells. After a period of 8, 14 and 35 weeks the kidneys were examined for BrdU by immunofluorescence and the four differentiation markers mentioned above. All cycling cells showed the same degree of differentiation compared to non-cycling cells. Most of the detected label-retaining cells were differentiated. We conclude that cycling cells in tubules of the healthy kidney are differentiated and that the retention of label is not a criterion to identify stem cells in renal tubules.