Altered expression of key cell cycle regulators in renal cell carcinoma associated with Xp11.2 translocation
Laboratório de Anatomia Patológica, Al. Hernani Monteiro 4200-451, Hospital de S. João, Porto, Portugal.Pathology - Research and Practice (Impact Factor: 1.4). 03/2009; 205(7):466-72. DOI: 10.1016/j.prp.2009.01.005
Renal cell carcinoma (RCC) is a rare tumor in the pediatric population. Recently, a phenotypically and genetically distinct kidney carcinoma, mainly prevalent in children and associated with an Xp11.2 translocation or TFE3 gene fusion, has been described. It has been advanced that in this subtype of RCC, there is an accumulation of cyclin D1, cyclin D3, and p21 ((wafl/cip1)). The aim of the present study was to figure out in two pediatric RCC recently diagnosed in our department (one clear cell-type RCC and one TFE3-positive RCC) whether those features are indeed specific of the latter tumor or occur in pediatric RCC irrespective of the tumor type. The following immunostains were performed in both cases: Ki67, p16(ink4a), p21 ((wafl/cip1)), p27(kip1), p53, p63, mdm2, cyclin D1, cyclin D3, TFE3, CD10, vimentin, E-cadherin, and RCC-antigen. We observed in the TFE3-positive carcinoma an intense immunoreaction for p21 ((wafl/cip1)), cyclin D1, and cyclin D3, without expression for p53, p16, p27(kip1), and mdm2, whereas the immunoexpression profile observed in the classic RCC was similar to that of clear cell, adult-type RCC. Our study confirms that TFE3-positive RCC exhibits a deregulation of the cell cycle apparently unrelated to the young age of the patients.
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ABSTRACT: Objective To confirm feasibility of Cyclin D1 gene as a new target for cancer gene therapy and to verify the effectiveness of shRNA expression vector-mediated gene silencing. Methods A RNA interference DNA template targeting Cyclin D1 gene was designed and synthesized. By ligation, the fragment was inserted into Pgenesil-1-U6 to constract the recombinant plasmid Pgenesil-shRNA-Cyclin D1. The identified recombinant plasmid was transfected into ACHN cells with lipofactamine. Cyclin D1 mRNA and protein expression was analyzed by RT-PCR and western-blotting. MTT method was used for observing cell proliferation and drawing growth curve. The cell cycle and ratios of apoptotic cell were assessed by flow cytometric detection. The ability of invasion of cell migration was detected by Transwell chamber invasive models. Results The plasmid was constructed successfully. After interference, The expression rate of Cyclin D1 mRNA decreased to 0.10±0.04 in Cyclin D1-shRNA(experimental) group and were significantly lower than Pgenesil-NC (negative) group (0.92±0.03) and ACHN (blank control) group(0.94±0.04)(P<0.05). As well, the expression rate of Cyclin D1 protein was decreased evidently in experimental group. The results of flow cytometric detection showed that, including early and late apoptotic cells, the apoptotic ratio of experimental group increased to (37.26±0.60)% significantly, while, the negative group and blank control group were only (4.62±0.40)% and (5.95±1.20)%, respectively. The cell growth curves indicated that the proliferation of experimental group cells was inhibited significantly(P<0.05) and Transwell results suggested that the abilities of invasion cells transfected with Pgenesil-CyclinD1-shRNA decreased conspicuously(P<0.05). Conclusion The shRNA can inhibit Cyclin D1 expression, specifically and persistently. The down-regulation of Cyclin D1 expression can inhibit the proliferation and induce the apoptosis of renal cell adenocarcinoma cell line ACHN.
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ABSTRACT: Xp11 translocation renal cell carcinoma (RCC) harbor various TFE3 gene fusions, and are known to underexpress epithelial immunohistochemical (IHC) markers such as cytokeratin and EMA relative to usual adult type RCC; however, their profile in reference to other IHC markers that are differentially expressed in other subtypes of RCC has not been systematically assessed. Few therapeutic targets have been identified in these aggressive cancers. We created 2 tissue microarrays (TMA) containing five 1.4-mm cores from each of 21 Xp11 translocation RCC (all confirmed by TFE3 IHC, 6 further confirmed by genetics), 7 clear cell RCC (CCRCC), and 6 papillary RCC (PRCC). These TMA were labeled for a panel of IHC markers. In contrast to earlier published data, Xp11 translocation RCC frequently expressed renal transcription factors PAX8 (16/21 cases) and PAX2 (14/21 cases), whereas only 1 of 21 cases focally expressed MiTF and only 5 of 21 overexpressed p21. Although experimental data suggest otherwise, Xp11 translocation RCC did not express WT-1 (0/21 cases). Although 24% of Xp11 translocation RCC expressed HIF-1alpha (like CCRCC), unlike CCRCC CA IX expression was characteristically only focal (mean 6% cell labeling) in Xp11 translocation RCC. Other markers preferentially expressed in CCRCC or PRCC, such as HIG-2, claudin 7, and EpCAM, yielded inconsistent results in Xp11 translocation RCC. Xp11 translocation RCC infrequently expressed Ksp-cadherin (3/21 cases) and c-kit (0/21 cases), markers frequently expressed in chromophobe RCC. Using an H-score that is the product of intensity and percentage labeling, Xp11 translocation RCC expressed higher levels of phosphorylated S6, a measure of mTOR pathway activation (mean H score=88), than did CCRCC (mean H score=54) or PRCC (mean H score=44). In conclusion, in contrast to prior reports, Xp11 translocation RCC usually express PAX2 and PAX8 but do not usually express MiTF. Although they may express HIF-1alpha, they only focally express the downstream target CA IX. They inconsistently express markers associated with other RCC subtypes, further highlighting the lack of specificity of the latter markers. TFE3 and Cathepsin K remain the most sensitive and specific markers of these neoplasms. Elevated expression of phosphorylated S6 in Xp11 translocation RCC suggests the mTOR pathway as an attractive potential therapeutic target for these neoplasms.
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ABSTRACT: The 2004 World Health Organization classification includes the new entity "neuroblastoma-associated renal cell carcinoma." The pathogenetic link between these entities is unknown as yet. The patient reported herein developed renal cell carcinoma after anaplastic embryonal rhabdomyosarcoma, a previously unknown association. The 2nd malignancy developed very soon after the 1st one, prompting concern for inherent cancer predisposition rather than a therapy-induced 2nd malignancy. A variety of features raised suspicion for Tp53 mutation, and indeed a pathogenic germline Tp53 mutation was identified in this child, despite a negative family history for Li-Fraumeni syndrome. Consideration of underlying predisposition is advocated in the context of rapid evolution of 2nd childhood malignancy.
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