Sonic hedgehog medulloblastoma encompasses a clinically and molecularly diverse group of cancers of the developing central nervous system. Here, we use unbiased sequencing of the transcriptome across a large cohort of 250 tumors to reveal differences among molecular subtypes of the disease, and demonstrate the previously unappreciated importance of non-coding RNA transcripts. We identify alterations within the cAMP dependent pathway (GNAS, PRKAR1A) which converge on GLI2 activity and show that 18% of tumors have a genetic event that directly targets the abundance and/or stability of MYCN. Furthermore, we discover an extensive network of fusions in focally amplified regions encompassing GLI2, and several loss-of-function fusions in tumor suppressor genes PTCH1, SUFU and NCOR1. Molecular convergence on a subset of genes by nucleotide variants, copy number aberrations, and gene fusions highlight the key roles of specific pathways in the pathogenesis of Sonic hedgehog medulloblastoma and open up opportunities for therapeutic intervention.
The aim of this retrospective study was to compare the incidence of chromosomal abnormality in embryos from in-vitro maturation (IVM) and IVF cycles. The copy numbers of chromosomes 13, 15, 16, 18, 21, 22, X and Y were assessed with fluorescence in-situ hybridization (FISH) in single blastomeres biopsied from cleavage stage embryos. Spare embryos that were not transferred or cryopreserved were also analysed in full. IVM and IVF groups comprised six and 30 couples, with mean ± SD embryos with FISH result of 8.0 ± 4.4 and 11.7 ± 3.8, respectively. The incidence of chromosomal abnormality per FISH result was similar in IVM and IVF embryos (58.7% versus 57.4%, respectively). When embryos were categorized based on maturation time of oocytes in IVM cycles, embryos derived from oocytes that matured 48 h after collection had a higher chromosomal abnormality rate compared with embryos derived from in-vivo matured oocytes and to embryos derived from oocytes that matured in the first 24 h after collection.
The expression of growth-differentiating factor 9 (GDF9) has not been studied in ovaries from girls and human fetuses nor has its receptor transforming growth factor-beta1 receptor (TGFbetaR1) been investigated in ovaries of girls/women. The aim of this study was to fill these gaps. Ovarian samples were obtained from 16 human fetuses at 21-35 gestational weeks and from 34 girls/women aged 5-39years. These specimens were prepared for immunohistochemical staining of the GDF9 and TGFbetaR1 proteins. Reverse transcription polymerase chain reaction was used to detect GDF9 mRNA transcripts and in-situ hybridization to localize TGFbetaR1 mRNA transcripts. Positive staining for the GDF9 protein was identified in oocytes and granulosa cells in all samples tested. GDF9 mRNA transcripts were present in all samples. Protein expression of TGFbetaR1 was identified in granulosa cells in all samples. Oocyte staining was identified in samples from girls/women but in only one fetal sample. TGFbetaR1 mRNA transcripts were identified in granulosa cells and oocytes in 50% of the samples from fetuses aged over 22 gestational weeks and in samples from girls/women. The detection of GDF9 and TGFbetaR1 at both at the protein and mRNA levels suggests that GDF9 may have functions in human preantral follicles.
The objective of this retrospective study was to investigate the incidence and clinical implications of multinucleation in blastomeres biopsied from cleavage-stage embryos obtained from patients undergoing preimplantation genetic screening (PGS) for aneuploidies or preimplantation genetic diagnosis (PGD) for translocations or single-gene defects (SGD). A total of 3515 embryos were obtained from 306 couples in 380 PGD or PGS cycles. Incidence of multinucleation, chromosomal complement in multinucleated (MN) and sibling embryos and the characteristics of MN embryos resulting in healthy births were investigated. Of all cycles, 41.3% involved at least one MN embryo. There were more uniformly diploid than uniformly haploid nuclei (22.0% versus 7.9%, P<0.01). The most common form of abnormality was chaotic chromosomal complement (39.9%, 147/368). Transfer of embryos that had MN blastomeres free of the genetic abnormalities tested resulted in three healthy deliveries. It is concluded that, although the majority of MN blastomeres are chromosomally abnormal, healthy births are possible after transfer of embryos containing these blastomeres subjected to genetic analysis. As far as is known, this is the first report of healthy births after transfer of embryos with MN blastomeres tested for translocations or SGD in PGD cycles. Preimplantation genetic diagnosis (PGD) is an established method for selecting genetically healthy embryos for transfer. A blastomere sampled from the developing embryo is subjected to genetic analysis. Some of these blastomeres may contain multiple nuclei, complicating the genetic diagnosis. We investigated clinical implications of multinucleation in PGD cycles. Our results indicate that majority of the multinucleated blastomeres, and consequently embryos, are genetically abnormal. However, healthy births are possible after transfer of multinucleated embryos that are free of the genetic abnormalities screened.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.