Nika Kojc

Cadherin–catenin complex and transcription factor Snail-1 in spindle cell carcinoma of the head and neck

Spindle cell carcinoma (SpCC) is a biphasic tumor composed of squamous cell carcinoma (SCC) and a malignant spindle cell component. There is mounting evidence that SpCC is a monoclonal neoplasm originating from a stem cell giving rise to both components. We tested the hypothesis that spindle cell phenotype might be related to the cadherin–catenin complex, which forms adherens junctions between cells. We analyzed the immunohistochemical expression of E- and N-cadherin, α-, β- and γ-catenin, and Snail-1, a transcription repressor of E-cadherin, in 30 cases of SpCC, and 30 cases of SCC of the head and neck. In SpCC, cadherin and catenin expression was similar in the SCC component, whereas in the spindle cell component, loss of E-cadherin and neo-expression of N-cadherin was found in 19 cases, loss of cadherins in seven, and their co-expression in four cases. Catenin expression were altered in 18 SpCCs. Snail-1 was found in 19 SpCC cases. In SCC, E-cadherin and catenins were expressed in all cases, and N-cadherin focally in five cases. Snail-1 was observed in the stroma. To summarize, in SpCC, there is an altered expression of the cadherin–catenin complex, associated with morphological transition from epithelial to spindle cell phenotype. These features are reminiscent of epithelial–mesenchymal transition (EMT). Our study thus indicates that EMT might play an important role in the pathogenesis of SpCC. This conclusion is further supported by our finding of Snail-1 expression, a potent inducer of EMT, in more than half SpCC cases.

Down-regulation of microRNAs of the miR-200 family and miR-205, and an altered expression of classic and desmosomal cadherins in spindle cell carcinoma of the head and neck--hallmark of epithelial-mesenchymal transition.

MicroRNAs are small, noncoding RNAs that regulate gene expression by posttranscriptional regulation of target genes. miR-200 family and miR-205 have been shown experimentally to regulate epithelial-mesenchymal transition. As epithelial-mesenchymal transition is the postulated pathogenetic mechanism in spindle cell carcinoma, we analyzed the expression of these microRNAs in spindle cell carcinoma of the head and neck in comparison to conventional squamous cell carcinoma of similar location and stage. We also analyzed the expression of classic and desmosomal cadherins, which are believed to be important targets during epithelial-mesenchymal transition. Forty-five cases of spindle cell carcinoma and 45 cases of squamous cell carcinoma of the head and neck were analyzed using real-time polymerase chain reaction for microRNAs, and immunohistochemistry for classic cadherins (E- and N-cadherins) and desmosomal cadherins. We found a significant down-regulation of the miR-200 family and miR-205, loss of desmosomal cadherins, and an altered expression of classic cadherins in spindle cell carcinoma in comparison to squamous cell carcinoma. Down-regulation of the miR-200 family and miR-205 strongly supports the postulated role of epithelial-mesenchymal transition in spindle cell carcinoma. These microRNAs act on transcription repressors that were also up-regulated in our cases of spindle cell carcinoma, both on mRNA and on protein levels. The result is not only an altered expression of classic cadherins in adherens junctions but also a complete loss of desmosomal cadherins.

Transcription factors Snail, Slug, Twist, and SIP1 in spindle cell carcinoma of the head and neck.

Spindle cell carcinoma (SpCC) is a biphasic tumor composed of squamous cell carcinoma (SCC) and malignant spindle cells. There is mounting evidence that epithelial–mesenchymal transition (EMT) plays an important role in the pathogenesis of SpCC. Transcription repression has recently emerged as a fundamental mechanism triggering EMT in experimental models. Our aim is to analyze the expression of transcription repressors Snail, Slug, Twist, and SIP1 in SpCC of the head and neck in comparison to SCC, matched for location and stage. Thirty cases of SpCC and 30 cases of SCC of the head and neck were included. Snail, Slug, Twist, and SIP1 expression was analyzed on mRNA and protein levels, using real-time reverse transcription–polymerase chain reaction (RT-PCR) and immunohistochemistry. By RT-PCR, we found upregulation of mRNA for transcription factors Snail, Slug, Twist, and SIP1 in SpCC when compared to SCC. This upregulation was statistically significant for Slug, Twist, and SIP1 but nonsignificant for Snail. Immunohistochemistry was performed for Snail, Slug, and SIP1 and demonstrated a positive reaction for Slug and SIP1 in all cases and for Snail in two thirds of SpCC cases. Our finding of upregulation of all four tested transcription factors supports the hypothesis that EMT plays an important role in the pathogenesis of SpCC of the head and neck.

Down‐regulation of microRNAs of the miR‐200 family and up‐regulation of Snail and Slug in inflammatory bowel diseases — hallmark of epithelial−mesenchymal transition

Fibrosis is an important feature of inflammatory bowel diseases (IBD), particularly Crohns disease (CD), but its pathogenesis is poorly understood. To determine the postulated involvement of epithelial−mesenchymal transition (EMT) in the development of fibrosis in IBD, we analysed the expression profiles of the miR‐200 family which has been shown to induce EMT in experimental models and various human diseases. We also analysed the expression of Snail and Slug, postulated targets of the investigated microRNAs. Ten patients with ulcerative colitis (UC) and 10 patients with CD who underwent colon resection were included. From each, two tissue samples were chosen (one with the most severely and one with the least affected or normal mucosa) for analysis of microRNAs expression using real‐time polymerase chain reaction, and Snail and Slug expression using immunohistochemistry. We found significant down‐regulation of all investigated microRNAs in CD, and of three investigated microRNAs in UC, in comparison to the normal or the least affected mucosa. Comparing UC and CD, four microRNAs were significantly more down‐regulated in CD than in UC. Snail and Slug were expressed in the injured epithelium and occasionally in mesothelial cells and submesothelial fibroblasts. Our finding of down‐regulation of the miR‐200 family and up‐regulation of transcription repressors Snail and Slug supports the postulated role of EMT in the pathogenesis of fibrosis in IBD. The described expression patterns are consistent with the notion that fibrosis does not occur only in CD but also in UC, being much more severe in CD.

Diagnosing cytomegalovirus in patients with inflammatory bowel disease—by immunohistochemistry or polymerase chain reaction?

Cytomegalovirus (CMV) reactivation is a common complication in patients with inflammatory bowel diseases (IBD), particularly in those with steroid-resistant ulcerative colitis. It is usually diagnosed by histopathologic and immunohistochemical examination of the colon biopsy. The introduction of quantitative, real-time polymerase chain reaction (qPCR) has been recommended to improve the sensitivity, but there is little consensus on how to use it. We compared the two methods in samples from resected bowel of patients with IBD. Twelve patients with IBD who had undergone bowel resection were analysed for CMV, using qPCR and immunohistochemistry. In all cases, tissue samples from the base and the edge of ulcers and from uninvolved mucosa were obtained. The highest densities of CMV-positive cells were found in samples from the base of ulcers (immunohistochemistry 0–0.47 positive cells/mm2; qPCR 10–3809 viral copies/mg) or the edge of ulcers (immunohistochemistry 0.06–0.32 positive cells/mm2; qPCR 35–1049 viral copies/mg). In samples of uninvolved mucosa, immunohistochemistry was negative, whereas qPCR was either negative or showed very low values (0–3 viral copies/mg). We conclude that both immunohistochemistry and qPCR can be successfully used for diagnosing CMV reactivation in patients with IBD. The base and the edge of ulcers are the optimal sites for endoscopic biopsies. The density of CMV-positive cells was low and their distribution within the colon uneven. It therefore seems that the number of sampled biopsies and/or the number of investigated levels is more important that the choice of diagnostic method.

AA amyloidosis in a polyarteritis nodosa patient treated with tocilizumab.

Abstract Amyloid A (AA) (secondary) amyloidosis represents a severe complication of chronic inflammatory diseases. Since pathogenic mechanisms point to the central role of interleukin 6 (IL-6) in the process of amyloid AA generation, IL-6 blockade seems an attractive therapeutic option. We report a case of a patient with polyarteritis nodosa complicated by AA amyloidosis treated with tocilizumab.

Severe active C3 glomerulonephritis triggered by immune complexes and inactivated after eculizumab therapy

BackgroundUnderstanding the role of alternative complement pathway dysregulation in membranoproliferative glomerulonephritis (MPGN) has led to a dramatic shift in its classification into two subgroups: immune complex-mediated MPGN and complement-mediated MPGN, consisting of dense deposit disease and C3 glomerulonephritis (C3GN). A limited number of C3GN cases have been published to date with not yet conclusive results since the novel therapeutic approach with eculizumab was introduced.Case presentationWe report the clinical follow-up of a 16-year-old patient in whom a diagnosis of C3GN was confirmed by immunofluorescence and electron microscopy in second and third kidney biopsies, while the first biopsy revealed idiopathic immune complex-mediated MPGN type III, Anders and Strife variant, which failed to improve after several attempts at conventional immunosuppression therapy. Although applied late in an already fairly advanced stage of the severe active form of MPGN, the efficacy of eculizumab on C3GN was evidenced clinically and pathohistologically. Its beneficial influence on pathomorphogenesis was demonstrated by a unique follow-up in the last three biopsies, despite the recent observation, confirmed in this study, of eculizumab binding within the kidney tissue.ConclusionsClinicians and pathologists should be aware that, in some patients, an underlying genetic or acquired complement alternative pathway abnormality can be masked by an initial immune complex-mediated mechanism, which subsequently triggers an unbalanced excessive continual driving of complement terminal pathway activation and the development of C3GN. In such a patient, supplementary steroids in addition to eculizumab appear necessary to achieve an adequate response.

Pacinioma of the cauda equina.

Lesions composed of Pacinian corpuscles or showing Pacinian corpuscle differentiation have usually been described in relation to benign tumours of the peripheral nervous system or reactive hyperplastic processes. On the other hand, mature Pacinian corpuscles have occasionally been detected as part of intraspinal lumbosacral lipomas, a rare developmental anomaly usually associated with spina bifida. A lesion of the cauda equina composed of numerous mature Pacinian corpuscles and nerve fascicles embedded in adipose tissue in association with spina bifida occulta is described in a 5-month-old male with a sacral red papula. Magnetic resonance imaging (MRI) revealed a cord-like mass in the region of the cauda equina, presumably connected to the subcutis. With the exception of a low lying, tethered spinal cord, there was no neurological deficit and the range of motor development was normal. In March 2005, at 17 months, surgery was carried out. A cord of yellow tissue was found running from the subcutis through the bone defect into the lumbosacral spinal canal. Intradurally, it ran parallel to the cauda equina, terminating at the conus medullaris. Fifteen months after the surgery the development of the child was normal. Only two similar cases have been reported so far. Due to their occurrence in the sacrococcygeal region and association with developmental anomalies, they have been regarded as malformations and the term Pacinioma has been suggested. Our case with clusters of Pacinian corpuscles may represent a rare variant of complex intraspinal lumbosacral lipomas, closely related to Paciniomas reported by Bale.

Tubular urinary indexes reliably distinguish between primary tubulointerstitial and primary glomerular diseases in patients referred for kidney biopsy

AIMS Kidney biopsy remains the gold standard for accurately diagnosing renal diseases. Urinalysis and assessment of renal function are the cornerstones for assessment of patients prior to biopsy. There is significant overlap in the results of routine urine parameters (proteinuria, erythrocyturia, leukocyturia) among different kidney diseases, which hinders the possibility of adequately estimating disease etiology prior to the biopsy. The aim of our study was to assess whether diverse markers of glomerular and tubular proteinuria - urinary albumin, IgG, α-1-microglobulin (α-1-m) and N-acetyl-β-D-glucosaminidase (NAG) - are capable of distinguishing between patients with primary tubulointerstitial (TID) and primary glomerular disease (GLOM). METHODS Our study is a retrospective, single-center, consecutive case series of patients referred for kidney biopsy. We analyzed routine urinalysis results performed on a second morning urine sample immediately prior to the biopsy. RESULTS Patients with TID had significantly higher values of α-1-m and NAG, with lower values of albumin and IgG in the urine compared to patients with GLOM. Three tubular urinary indexes had high sensitivity and specificity for distinguishing TID from GLOM: NAG/albumin, α-1-m/proteinuria, and α-1-m/albumin, with the highest values in the latter index (96.6% and 98.2%, respectively, cut-off point ≥ 0.33). CONCLUSIONS Prior to kidney biopsy, tubular urinary indexes may present a valuable tool in distinguishing patients with TID from patients with GLOM.
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