Search Results - EGA European Genome-Phenome Archive

Cholangiocarcinomas (CCAs) is a type of cancer with few effective systemic therapies. Elucidation of the molecular landscape of the disease from genomic studies based on next generation sequencing (NGS) has contributed to the introduction of new targeted therapies. One of these treatments consists of a class of small molecules that target members of the FGFR family of receptor tyrosine kinases. These drugs are effective and have been approved for cholangiocarcinomas with fusions or rearrangements of FGFR genes. In contrast, the role of these inhibitors in cholangiocarcinomas with mutations in FGFR genes is less well defined. We report here a patient with a cholangiocarcinoma bearing a FGFR2 p.Ser252Trp mutation. The patient was treated with two different FGFR inhibitors, as the first caused ocular toxicity. She obtained clinical benefit from both. This case illustrates the efficacy of FGFR inhibitors on cholangiocarcinoma with specific point mutations. This is the first case to report the clinical benefit of these drugs in FGFR2 p.Ser252Trp mutation. Clinical benefit can be sustained, as seen in our patient. Our case also shows that FGFR inhibitors-induced adverse effects, such as ocular toxicities, may not recur after re-challenge with an alternative drug of the same class.

Dataset EGAD50000000021

Clonal selection after gene therapy in sickle cell disease

While gene therapy (GT) provides a potentially curative treatment option for patients with sickle cell disease (SCD), the occurrence of myeloid malignancies in clinical trials has prompted concern. To interrogate potential mechanisms underlying increased cancer risk, we used hematopoietic stem cell (HSC) clonal tracking by whole genome sequencing (WGS) to map the somatic mutation and clonal landscape of 2,592 gene modified as well as unmodified single stem and progenitor cells from six SCD patients undergoing gene therapy (7-26 years old, average 12.7× depth). Pre-GT phylogenetic trees in SCD were highly polyclonal and mutation burdens per cell were elevated in some, but not all, patients. Post-GT, no clonal expansions were identified. However, an increased frequency of driver mutations associated with myeloid neoplasms or clonal hematopoiesis (DNMT3A- and EZH2-mutated clones in particular) were seen in both genetically modified and unmodified cells suggested positive selection of mutant clones during gene therapy. This work sheds light on the mutation landscape and HSC clonal dynamics in gene therapy for SCD and highlights enhanced fitness of some HSCs harboring pre-existing driver mutations following gene therapy. Future studies should define the long-term fate of mutant clones including any contribution to expansions associated with myeloid neoplasms.

Dataset EGAD00001010914

Location and Function of NSun2-Mediated Cytosine-5 Methylation in RNA and its Effect on Translation

Mutations in the cytosine-5 RNA methyltransferase NSun2 can cause neurodevelopmental disorders and symptoms commonly found in patients with Dubowitz-like syndrome. Some tRNAs are known to be methylated NSun2, however the occurrence of cytosine-5 methylation (m5C) in other RNA biotypes is still under debate. Location in RNA and function of m5C has not been studied yet. This study is aimed at identifying new m5C methylated RNA biotypes, as well as the location at specific structures or sequences and the ultimate biological function. The impact of the loss of NSun2-mediated methylation is also determined by comparing gene expression data with the global cytosine-5 RNA methylome in Dubowitz-like syndrome patients. We also use ribosomal profiling to assess the impact of the loss and rescue of Nsun2-mediated cytosine-5 RNA methylation on translation rates and ribosome occupancy.

Study phs000645

ChIP-Seq files for RMS.

ChIP-Seq files accompanying the paper titled "Identification of Therapeutic Targets in Rhabdomyosarcoma Through Integrated Genomic, Epigenomic, and Proteomic Analyses".

Dataset EGAD00001006398