Frequent ATRX mutations and loss of expression in adult diffuse astrocytic tumors carrying IDH1/IDH2 and TP53 mutations
ACTA NEUROPATHOLOGICA
Authors: Liu, Xiao-Yang; Gerges, Noha; Korshunov, Andrey; Sabha, Nesrin; Khuong-Quang, Dong-Anh; Fontebasso, Adam M.; Fleming, Adam; Hadjadj, Djihad; Schwartzentruber, Jeremy; Majewski, Jacek; Dong, Zhifeng; Siegel, Peter; Albrecht, Steffen; Croul, Sidney; Jones, David T. W.; Kool, Marcel; Tonjes, Martje; Reifenberger, Guido; Faury, Damien; Zadeh, Gelareh; Pfister, Stefan; Jabado, Nada
Abstract
Gliomas are the most common primary brain tumors in children and adults. We recently identified frequent alterations in chromatin remodelling pathways including recurrent mutations in H3F3A and mutations in ATRX (alpha-thalassemia/mental-retardation-syndrome-X-linked) in pediatric and young adult glioblastoma (GBM, WHO grade IV astrocytoma). H3F3A mutations were specific to pediatric high-grade gliomas and identified in only 3.4 % of adult GBM. Using sequencing and/or immunohistochemical analyses, we investigated ATRX alterations (mutation/loss of expression) and their association with TP53 and IDH1 or IDH2 mutations in 140 adult WHO grade II, III and IV gliomas, 17 pediatric WHO grade II and III astrocytomas and 34 pilocytic astrocytomas. In adults, ATRX aberrations were detected in 33 % of grade II and 46 % of grade III gliomas, as well as in 80 % of secondary and 7 % of primary GBMs. They were absent in the 17 grade II and III astrocytomas in children, and the 34 pilocytic astrocytomas. ATRX alterations closely overlapped with mutations in IDH1/2 (p < 0.0001) and TP53 (p < 0.0001) in samples across all WHO grades. They were prevalent in astrocytomas and oligoastrocytomas, but were absent in oligodendrogliomas (p < 0.0001). No significant association of ATRX mutation/loss of expression and alternative lengthening of telomeres was identified in our cohort. In summary, our data show that ATRX alterations are frequent in adult diffuse gliomas and are specific to astrocytic tumors carrying IDH1/2 and TP53 mutations. Combined alteration of these genes may contribute to drive the neoplastic growth in a major subset of diffuse astrocytomas in adults.
Evaluation of candidate reference genes for investigation of the uterine tissue and corpus luteum of pigs on day 6 after artificial insemination
ANIMAL REPRODUCTION SCIENCE
Authors: Okino, Cintia Hiromi; Guaratini Ibelli, Adriana Mercia; Brentano, Liana; Zanella, Ricardo; Marques, Mariana Groke
Abstract
Housekeeping genes (HKG) are genes necessary for the maintenance of basal cellular functions, regardless of the specific roles within a tissue. It, therefore, is expected that these genes will maintain a relatively constant expression profile when there are varying physiological conditions. The identification of tissue specific reference genes is highly important for the normalization of gene expression profiles among different tissues. In this sow study, the objective was to identify stable reference genes in the uterine tissue and corpus luteum (CL), 6 days post-artificial insemination. The stability of ubiquitin (UBB), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), DNA topoisomerase 2-beta (TOP2B), histone H3 (H3F3A) and hypoxanthine-guanine phosphoribosyltransferase 1 (HPRT1) abundances of mRNA were evaluated using the Bestkeeper technique. Briefly, total RNA was extracted for each tissue from 20 gilts (n = 20), processed by RT-qPCR and submitted to analysis using the Bestkeeper technique, which allowed for the evaluation of the consistency in abundance of mRNA for the reference genes. For all evaluated genes, the abundance of mRNA was relatively consistent in the uterine tissue, with the greatest abundance being for the GAPDH and TOP2B genes. The analysis of these genes in the CL, however, indicated there was a relatively greater variation of mRNA abundance for the various reference genes. Data suggest that UBB was the reference gene with the most consistent relative abundance of mRNA and that this gene could be used as a reference for corpora lutea analyses of mRNA.