Objective-Atypical teratoid/rhabdoid tumors are aggressive neoplasms of the central nervous system occurring mainly in the early childhood and rarely in adults. We described a case of this tumor in an 18-year-old male patient without previous medical history.Material-method-The neoplasm was localized in the right fronto-temporal area of the brain and was totally excised. The specimen was fixed in formalin and embedded in paraffin. The histological and immunohistochemical features of the neoplasm were assessed, while sequencing analysis as well as interphase fluorescence in situ hybridization (FISH) were performed. Conclusions-26 previous cases of ATRT have been reported in adults, thus far. To our knowledge, this is the eighth case of an ATRT reported in an adult patient having genetic confirmation and the first one in which the tumor is, partly, localized in the right temporal area of the brain. This unusual presentation underlines the necessity of considering this devastating neoplasm in the differential diagnosis of malignant brain tumors of young adults.
Results-Histological
BackgroundColorectal (CRC) carcinogenesis through various morphological stages has been linked to several genetic and epigenetic changes. The Raf/MEK/ERK (MAPK) signal transduction cascade is an important mediator of a number of cellular fates.MethodsIn this study, we investigated the presence of B-raf and K-ras mutations in 94 consecutive cases of primary colon adenocarcinoma in correlation with the immunohistochemical expression of total and activated ERK and the expression of mismatch repair proteins (MMR) hMLH1 and hMSH2 as well as their correlations with standard clinicopathological parameters.ResultsThe immunostaining pattern for total and activated ERK was nuclear and cytoplasmic. hMLH1 and hMSH2 proteins were preserved in 45/63 (71.43%) cases and 35/53 (66.04%) cases respectively. Total ERK nuclear expression, was positively correlated with tumor stage (p = 0.049), whereas nuclear pERK expression was positively correlated with histological grade (p = 0.0113) and tumor stage (p = 0.0952), although the latter relationship was of marginal significance. DNA sequencing showed that 12 samples (12.7%) had a mutation in B-RAF Exon 15 and none in Exon 11, whereas 22 (23.4%) had a K-ras mutation. Disruption of the MAP kinase pathway-either through K-ras or B-raf mutation-was detected in 37% of all the examined cases, although the overexpression of total and activated ERK1/2 was not correlated with the mutational status of K-ras or B-raf genes. Finally, the preservation of hMLH1 or hMSH2 immunoexpression was not correlated with the presence of B-raf and/or K-ras mutations.ConclusionsIn this study, we present evidence that ERK activation occurs in a K-ras or B-raf -independent manner in the majority of primary colon cancer cases. Moreover, B-raf mutations are not associated with mismatch-repair deficiency through loss of hMLH1 or hMSH2 expression. Activated ERK could possibly be implicated in tumor invasiveness as well as in the acquisition of a more aggressive phenotype.
Background: Clear cell renal cell carcinomas (ccRCCs) constitute the most common renal carcinomas, characterized by a relatively aggressive clinical course. Thus, scientific research is targeting towards the identification of immunohistochemical and molecular markers that could be useful regarding diagnosis, appropriate therapy and prediction of prognosis. In the present study we assessed and correlated the expression of caspase-8, phosphorylated p38 mitogen-activated protein kinase (p-p38) and bcl-2 protein with histopathological features and clinical outcome of 27 patients with ccRCCs.
Microsatellite instability (MSI) constitutes an alternative-to the chromosomal instability-pathway of carcinogenesis for certain tumour types with prognostic and therapeutic significance for the respective patients. MSI is caused by mutations in mismatch repair (MMR) genes, mainly hMLH1, hMSH2, leading to a defective MMR system. The role of MSI in basal cell carcinoma (BCC) has not been clearly delineated yet. p53 gene as a target for ultraviolet radiation-induced mutations may enhance genomic instability in BCC, with loss of its function. Our aim was to investigate the involvement of MSI and expression of hMLH1 and hMSH2 in parallel with P53 protein accumulation in the pathogenesis of BCC and its possible correlation to the clinicopathological features of the patients. The presence of MSI was investigated in 76 BCCs using mononucleotide microsatellite markers, BAT-25, BAT-26 and TGF-beta receptor type II (TGF-beta-RII). Additionally, 3 dinucleotide markers were analysed in 20 cases in which matched normal tissue was available. The expression of hMLH1, hMSH2 and P53 proteins was evaluated by immunohistochemical analysis. Alterations of the BAT-26 marker were observed in one fibroepithelioma of Pincus, one nodular and one multifocal superficial BCC. A keratotic BCC showed an altered BAT-25 locus. Two samples, a multifocal superficial and a nodular BCC, displayed MSI at two markers (BAT-25 and BAT-26; and BAT-25 and TGF-beta-RII, respectively). Three more cases, a metatypical, a multifocal superficial and a signet ring BCC exhibited frameshift mutations in the TGF-beta-RII. No sample showed length alterations at the dinucleotide markers examined. hMLH1 and hMSH2 protein immunohistochemical expression was scored positive in 46 and 49 out of 52 cases respectively. P53 accumulation was observed in 27 out of 56 samples. Correlation of the molecular and immunohistochemical findings with the clinicopathological parameters produced no statistically significant results. No correlation between MSI and hMLH1, hMSH2 or P53 protein expression was determined. MSI appears to play a minor role in the pathogenesis of BCCs being present only in a small subset of such tumours.
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