SMARCB1/INI1 inactivation in renal medullary carcinoma

Aims: Renal medullary carcinoma (RMC), a rare and highly aggressive tumour which occurs in patients with sickle-cell disease, shares many clinicopathological features with collecting duct carcinoma (CDC). The molecular mechanisms underlying RMC and CDC are mainly unknown, and there is ongoing debate about their status as distinct entities. Loss of expression of SMARCB1/INI1, a chromatin remodelling regulator and repressor of cyclin D1 transcription, has been reported recently in RMC. The aim of our study was to investigate if such loss of expression is specific for RMC. SMARCB1/INI1 genetic alterations and cyclin D1 expression were also studied. Methods and results: Using immunochemistry, neoplastic cells showed complete loss of SMARCB1/INI1 expression in all six cases of RMC but in only one of 22 cases of CDC. In two RMC cases investigated, comparative genomic hybridization demonstrated complete loss of one SMARCB1/INI1 allele, with no other genomic imbalances, and no mutations were found on the remaining allele. Cyclin D1 was expressed in all RMCs, suggesting that SMARCB1/INI1 inactivation may result in increased cyclin D1 transcription. Conclusions: The specific SMARCB1/INI1 inactivation observed in RMCs suggests that RMC and CDC are different entities

Mutations in BHD and TP53 genes, but not in HNF1β gene, in a large series of sporadic chromophobe renal cell carcinoma

BHD, TP53, and HNF1β on chromosome 17 were studied in 92 cases of renal cell carcinoma (46 chromophobe, 19 clear cell, 18 oncocytoma, and nine papillary). Six, thirteen, and zero cases had, respectively BHD, TP53, and HNF1β mutations, (84% mutations involved chromophobe), suggesting a role for BHD and TP53 in chromophobe subtype

Somatic Pairing of Chromosome 19 in Renal Oncocytoma Is Associated with Deregulated ELGN2-Mediated Oxygen-Sensing Response

Chromosomal abnormalities, such as structural and numerical abnormalities, are a common occurrence in cancer. The close association of homologous chromosomes during interphase, a phenomenon termed somatic chromosome pairing, has been observed in cancerous cells, but the functional consequences of somatic pairing have not been established. Gene expression profiling studies revealed that somatic pairing of chromosome 19 is a recurrent chromosomal abnormality in renal oncocytoma, a neoplasia of the adult kidney. Somatic pairing was associated with significant disruption of gene expression within the paired regions and resulted in the deregulation of the prolyl-hydroxylase ELGN2, a key protein that regulates the oxygen-dependent degradation of hypoxia-inducible factor (HIF). Overexpression of ELGN2 in renal oncocytoma increased ubiquitin-mediated destruction of HIF and concomitantly suppressed the expression of several HIF-target genes, including the pro-death BNIP3L gene. The transcriptional changes that are associated with somatic pairing of chromosome 19 mimic the transcriptional changes that occur following DNA amplification. Therefore, in addition to numerical and structural chromosomal abnormalities, alterations in chromosomal spatial dynamics should be considered as genomic events that are associated with tumorigenesis. The identification of EGLN2 as a significantly deregulated gene that maps within the paired chromosome region directly implicates defects in the oxygen-sensing network to the biology of renal oncocytoma

Genomic expression and single-nucleotide polymorphism profiling discriminates chromophobe renal cell carcinoma and oncocytoma

<p>Abstract</p> <p>Background</p> <p>Chromophobe renal cell carcinoma (chRCC) and renal oncocytoma are two distinct but closely related entities with strong morphologic and genetic similarities. While chRCC is a malignant tumor, oncocytoma is usually regarded as a benign entity. The overlapping characteristics are best explained by a common cellular origin, and the biologic differences between chRCC and oncocytoma are therefore of considerable interest in terms of carcinogenesis, diagnosis and clinical management. Previous studies have been relatively limited in terms of examining the differences between oncocytoma and chromophobe RCC.</p> <p>Methods</p> <p>Gene expression profiling using the Affymetrix HGU133Plus2 platform was applied on chRCC (n = 15) and oncocytoma specimens (n = 15). Supervised analysis was applied to identify a discriminatory gene signature, as well as differentially expressed genes. High throughput single-nucleotide polymorphism (SNP) genotyping was performed on independent samples (n = 14) using Affymetrix GeneChip Mapping 100 K arrays to assess correlation between expression and gene copy number. Immunohistochemical validation was performed in an independent set of tumors.</p> <p>Results</p> <p>A novel 14 probe-set signature was developed to classify the tumors internally with 93% accuracy, and this was successfully validated on an external data-set with 94% accuracy. Pathway analysis highlighted clinically relevant dysregulated pathways of c-erbB2 and mammalian target of rapamycin (mTOR) signaling in chRCC, but no significant differences in p-AKT or extracellular HER2 expression was identified on immunohistochemistry. Loss of chromosome 1p, reflected in both cytogenetic and expression analysis, is common to both entities, implying this may be an early event in histogenesis. Multiple regional areas of cytogenetic alterations and corresponding expression biases differentiating the two entities were identified. Parafibromin, aquaporin 6, and synaptogyrin 3 were novel immunohistochemical markers effectively discriminating the two pathologic entities.</p> <p>Conclusions</p> <p>Gene expression profiles, high-throughput SNP genotyping, and pathway analysis effectively distinguish chRCC from oncocytoma. We have generated a novel transcript predictor that is able to discriminate between the two entities accurately, and which has been validated both in an internal and an independent data-set, implying generalizability. A cytogenetic alteration, loss of chromosome 1p, common to renal oncocytoma and chRCC has been identified, providing the opportunities for identifying novel tumor suppressor genes and we have identified a series of immunohistochemical markers that are clinically useful in discriminating chRCC and oncocytoma.</p

: pathological features in human muscles at different delays after infection

The authors describe the pathological aspects of muscles of three patients infected with Trichinella murrelli. Biopsies were carried out at various intervals. Six weeks after infection, the muscular larvae were not encapsulated whereas encapsulation was seen 10 weeks after infection. Six years after infection, the larvae were still alive in a nurse cell surrounded by a very thick capsule. Fourteen years after infection, cuticular larvae remnants were seen in degenerating nurse cells. The late encapsulation of Trichinella murrelli in human muscles could explain some clinical differences noticed during the outbreak during which these three patients were infected

Trichinella murrelli: pathological features in human muscles at different delays after infection

The authors describe the pathological aspects of muscles of three patients infected with Trichinella murrelli. Biopsies were carried out at various intervals. Six weeks after infection, the muscular larvae were not encapsulated whereas encapsulation was seen 10 weeks after infection. Six years after infection, the larvae were still alive in a nurse cell surrounded by a very thick capsule. Fourteen years after infection, cuticular larvae remnants were seen in degenerating nurse cells. The late encapsulation of Trichinella murrelli in human muscles could explain some clinical differences noticed during the outbreak during which these three patients were infected

Universal

We report on a study of the influence of defects introduced in the CuO2 planes of cuprates in a wide range of hole dopings x. T_{\ab c} and electrical resistivity $\rho (T)$ measurements have been performed on electron-irradiated \ab{YBa}_{2}\ab{Cu}_{3}\ab{O}_{7-\delta } and \ab{Tl}_{2}\ab{Ba}_{2}\ab{CuO}_{6+x} single crystals. A universal scaling between the decrease in T_{\ab c} and \Delta \rho_{\ab{2D}}\times n, where $\Delta \rho _{2D}$ is the increase of the 2D resistance induced by the defects and n is the carrier concentration equal to x, is found for all the samples investigated here. This demonstrates that the hole content is the relevant parameter to describe the transport properties all over the phase diagram, in contradiction with a recent suggestion of a change in the number of carriers from x to $1-x$ at the optimal doping. Moreover, the analysis of our data suggests that strong scattering persists on the overdoped side.-