Isatuximab plus pomalidomide and dexamethasone in relapsed/refractory multiple myeloma patients with renal impairment: ICARIA-MM subgroup analysis

The randomized, phase 3 ICARIA-MM study investigated isatuximab (Isa) with pomalidomide and dexamethasone (Pd) versus Pd in patients with relapsed/refractory multiple myeloma and ≥2 prior lines. This prespecified subgroup analysis examined efficacy in patients with renal impairment (RI; estimated glomerular filtration rate <60 mL/min/1.73 m²). Isa 10 mg/kg was given intravenously once weekly in cycle 1, and every 2 weeks in subsequent 28-day cycles. Patients received standard doses of Pd. Median progression-free survival (PFS) for patients with RI was 9.5 months with Isa-Pd (n = 55) and 3.7 months with Pd (n = 49; hazard ratio [HR] 0.50; 95% confidence interval [CI], 0.30–0.85). Without RI, median PFS was 12.7 months with Isa-Pd (n = 87) and 7.9 months with Pd (n = 96; HR 0.58; 95% CI, 0.38–0.88). The overall response rate (ORR) with and without RI was higher with Isa-Pd (56 and 68%) than Pd (25 and 43%). Complete renal response rates were 71.9% (23/32) with Isa-Pd and 38.1% (8/21) with Pd; these lasted ≥60 days in 31.3% (10/32) and 19.0% (4/21) of patients, respectively. Isa pharmacokinetics were comparable between the subgroups, suggesting no need for dose adjustment in patients with RI. In summary, the addition of Isa to Pd improved PFS, ORR and renal response rates

Variants Within TSC2 Exons 25 and 31 Are Very Unlikely to Cause Clinically Diagnosable Tuberous Sclerosis

Inactivating mutations in TSC1 and TSC2 cause tuberous sclerosis complex (TSC). The 2012 international consensus meeting on TSC diagnosis and management agreed that the identification of a pathogenic TSC1 or TSC2 variant establishes a diagnosis of TSC, even in the absence of clinical signs. However, exons 25 and 31 of TSC2 are subject to alternative splicing. No variants causing clinically diagnosed TSC have been reported in these exons, raising the possibility that such variants would not cause TSC. We present truncating and in‐frame variants in exons 25 and 31 in three individuals unlikely to fulfil TSC diagnostic criteria and examine the importance of these exons in TSC using different approaches. Amino acid conservation analysis suggests significantly less conservation in these exons compared with the majority of TSC2 exons, and TSC2 expression data demonstrates that the majority of TSC2 transcripts lack exons 25 and/or 31 in many human adult tissues. In vitro assay of both exons shows that neither exon is essential for TSC complex function. Our evidence suggests that variants in TSC2 exons 25 or 31 are very unlikely to cause classical TSC, although a role for these exons in tissue/stage specific development cannot be excluded

Ontogenic changes in hematopoietic hierarchy determine pediatric specificity and disease phenotype in fusion oncogene-driven myeloid leukemia

Fusion oncogenes are prevalent in several pediatric cancers, yet little is known about the specific associations between age and phenotype. We observed that fusion oncogenes, such as ETO2–GLIS2, are associated with acute megakaryoblastic or other myeloid leukemia subtypes in an age-dependent manner. Analysis of a novel inducible transgenic mouse model showed that ETO2–GLIS2 expression in fetal hematopoietic stem cells induced rapid megakaryoblastic leukemia whereas expression in adult bone marrow hematopoietic stem cells resulted in a shift toward myeloid transformation with a strikingly delayed in vivo leukemogenic potential. Chromatin accessibility and single-cell transcriptome analyses indicate ontogeny-dependent intrinsic and ETO2–GLIS2-induced differences in the activities of key transcription factors, including ERG, SPI1, GATA1, and CEBPA. Importantly, switching off the fusion oncogene restored terminal differentiation of the leukemic blasts. Together, these data show that aggressiveness and phenotypes in pediatric acute myeloid leukemia result from an ontogeny-related differential susceptibility to transformation by fusion oncogenes. SIGNIFICANCE: This work demonstrates that the clinical phenotype of pediatric acute myeloid leukemia is determined by ontogeny-dependent susceptibility for transformation by oncogenic fusion genes. The phenotype is maintained by potentially reversible alteration of key transcription factors, indicating that targeting of the fusions may overcome the differentiation blockage and revert the leukemic state

Building the Future Therapies for Down Syndrome: The Third International Conference of the T21 Research Society

Research focused on Down syndrome has increased in the last several years to advance understanding of the consequences of trisomy 21 (T21) on molecular and cellular processes and, ultimately, on individuals with Down syndrome. The Trisomy 21 Research Society (T21RS) is the premier scientific organization for researchers and clinicians studying Down syndrome. The Third International Conference of T21RS, held June 6–9, 2019, in Barcelona, Spain, brought together 429 scientists, families, and industry representatives to share the latest discoveries on underlying cellular and molecular mechanisms of T21, define cognitive and behavioral challenges and better understand comorbidities associated with Down syndrome, including Alzheimer’s disease and leukemia. Presentation of cutting-edge results in neuroscience, neurology, model systems, psychology, cancer, biomarkers and molecular and phar­ma­cological therapeutic approaches demonstrate the compelling interest and continuing advancement in all aspects of understanding and ameliorating conditions associated with T21

Building the Future Therapies for Down Syndrome:The Third International Conference of the T21 Research Society

Research focused on Down syndrome has increased in the last several years to advance understanding of the consequences of trisomy 21 (T21) on molecular and cellular processes and, ultimately, on individuals with Down syndrome. The Trisomy 21 Research Society (T21RS) is the premier scientific organization for researchers and clinicians studying Down syndrome. The Third International Conference of T21RS, held June 6-9, 2019, in Barcelona, Spain, brought together 429 scientists, families, and industry representatives to share the latest discoveries on underlying cellular and molecular mechanisms of T21, define cognitive and behavioral challenges and better understand comorbidities associated with Down syndrome, including Alzheimer's disease and leukemia. Presentation of cutting-edge results in neuroscience, neurology, model systems, psychology, cancer, biomarkers and molecular and phar-ma-cological therapeutic approaches demonstrate the compelling interest and continuing advancement in all aspects of understanding and ameliorating conditions associated with T21

Analysis of the binding of MutS to cisplatin-modified DNA

International audienc

Crystal structure of a double-stranded DNA containing a cisplatin interstrand cross-link at 1.63 A resolution: hydration at the platinated site.

cis-diamminedichloroplatinum (II) (cisplatin) is a powerful anti-tumor drug whose target is cellular DNA. In the reaction between DNA and cisplatin, covalent intrastrand and interstrand cross-links (ICL) are formed. Two solution structures of the ICL have been published recently. In both models the double-helix is bent and unwound but with significantly different angle values. We solved the crystal structure at 100K of a double-stranded DNA decamer containing a single cisplatin ICL, using the anomalous scattering (MAD) of platinum as a unique source of phase information. We found 47 degrees for double-helix bending and 70 degrees for unwinding in agreement with previous electrophoretic assays. The crystals are stabilized by intermolecular contacts involving two cytosines extruded from the double-helix, one of which makes a triplet with a terminal G.C pair. The platinum coordination is nearly square and the platinum residue is embedded into a cage of nine water molecules linked to the cross-linked guanines, to the two amine groups, and to the phosphodiester backbone through other water molecules. This water molecule organization is discussed in relation with the chemical stability of the ICL

Activating mutations in human acute megakaryoblastic leukemia

Oncogenic activation of tyrosine kinase signaling pathway is recurrent in human leukemia. To gain insight into the oncogenic process leading to acute megakaryoblastic leukemia (AMKL), we performed sequence analyses of a subset of oncogenes known to be activated in human myeloid and myeloproliferative disorders. In a series of human AMKL samples from both Down syndrome and non-Down syndrome patients, mutations were identified within KIT, FLT3, JAK2, JAK3, and MPL genes, with a higher frequency in DS than in non-DS patients. The novel mutations were analyzed using BaF3 cells, showing that JAK3 mutations were activating mutations. Finally, we report a novel constitutively active MPL mutant, MPLT487A, observed in a non-Down syndrome childhood AMKL that induces a myeloproliferative disease in mouse bone marrow transplantation assay

A subgroup of malignant fibrous histiocytomas is associated with genetic changes similar to those of well-differentiated liposarcomas

Increasing clinical and pathological evidence suggests that malignant fibrous histiocytomas (MFH) comprise a heterogeneous tumor group. In a series of 108 MFH tested by comparative genomic hybridization, we found in 22 tumors high-level coamplification of the 12q14 approximately q15 chromosome region with other loci, a genetics strongly reminiscent of what has been observed for well-differentiated liposarcomas. Nevertheless, these MFH differ from liposarcomas by a high recurrence of coamplified partners because coamplified loci were seen at 1p32 in nine cases, 6q23 in seven cases, and 12q24 in six cases. The same recurrence was observed in a series of dedifferentiated liposarcomas, but not in a series of well-differentiated liposarcomas. These observations demonstrate that a subgroup of MFH share a genetic partner very similar to that observed in liposarcomas, and suggest that the undifferentiated status of these tumors is closely related to the amplifications of specific chromosome loc