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Background: The SARS-CoV-2 outbreak significantly affected Gustave Roussy cancer center Here, we report the Gustave Roussy experience on older patients (OP) with cancer during the SARS-CoV-2 outbreak Methods: Cancer pts with suspected SARS-CoV-2 infection were admitted at Gustave Roussy starting March, 12th Screening indications have been adapted over time All the COVID-19 pts positively tested and managed at Gustave Roussy between March 14th and April 15th have been included in a redcap database Pts and underlying oncological and COVID-19 diseases characteristics have been collected Cancer and COVID-19 managements, and outcomes have been assessed The primary endpoint of this analysis was the clinical deterioration, defined as the need for O2 supplementation of 6l/min or more, or death of any cause Results: Among the first 137 cancer pts diagnosed with SARS-CoV-2, 36 patients were aged 70 years old or over (26%) Most of them were female (61%) with a median age of 75 5 years old Most frequent underlying cancers were solid tumors (92%) including GI (19%), lung (17%), GYN (14%) and head and neck (14%) Most OP (36%) were ECOG Performans status 2 versus 24% in younger patients (YP) The diagnosis of SARS-CoV-2 infection was made by RT-PCR or thoracic CT scan alone in 97% and 3% of the cases, respectively in OP and in 92% and 8% in YP Most OP experienced symptoms prior to testing (92%) compared to YP (80%) Symptoms differed according to age with more cough with sputum production in OP (14% versus 5%), dyspnea (39% versus 31%), diarrhea (17% versus 9%), shivers (8% versus 0%), sore throat (8% versus 4%) and no anosmia nor agueusia The majority of OP was hospitalized (81%) compared to 72% of YP and treated with HCQ/AZI (15;52%) compared to 25 (35%) YP with inclusion in the ONCOVID trial (EudraCT: 2020-01250-21) They did not receive any IL-6 inhibitor Only one OP was admitted in the ICU (3%) Clinical deterioration occurred in 10 OP (29%) There was no impact of age on clinical worsening (HR=1 157;95%CI 0 55-2 42;p=0 7) However age was associated with worse overall survival (OS) (HR=2 45 95%CI 1 02-5 92;p=0 0463) Results will be updated at the meeting Conclusions: OP with cancer had a different disease presentation, same rate of clinical worsening but worse OS in SARS-CoV-2 infection Legal entity responsible for the study: The authors Funding: Has not received any funding Disclosure: All authors have declared no conflicts of interest

Heterozygous non-synonymous (p.S142F) mutation in HNF1A leads to maturity-onset diabetes of the young (MODY) type 3, which is a subtype of dominant inherited young-onset non-autoimmune diabetes due to the defect of insulin secretion from pancreatic beta cells. We generated induced pluripotent stem cells (iPSCs) from a patient with HNF1A p.S142F mutation. Cells from this patient, which were reprogrammed by non-integrative viral transduction had normal karyotype, harboured the HNF1A p.S142F mutation, expressed pluripotency hallmarks.

Summary: MEN2A is a hereditary cancer-predisposing syndrome that affects patients with germline RET mutations. The effects of this oncogenic tyrosine kinase in the context of primitive stem cells are not known. In order to study these events, we generated a MEN2A induced Pluripotent Stem Cell (iPSC) line from a patient with RET mutation and an isogenic counterpart by CRISPR-Cas9 correction of the mutation. Whole exome sequencing of iPSC before and after CRISPR-Cas9 genome edition revealed no major exonic off target effect of the CRISPR correction. However, an integrative differential gene expression analysis of iPSC with oncogenic RETC634Y and its gene-corrected iPSC with RETY634C as well as RETwt iPSCs revealed activation of the Early Growth Response 1 (EGR1) transcriptional program in RET-mutated iPSC, a pathway shown to be involved in RET-induced oncogenesis. These data constitute the first proof of concept of the feasibility of the use of an iPSC and its genome-corrected counterpart to unravel the molecular mechanisms underlying the development of the hereditary MEN2A cancer predisposing syndrome.

We report here the first use of whole-genome sequencing (WGS) to examine the initial clonal dynamics in an unusual patient with chronic myeloid leukemia (CML), who presented in chronic phase (CP) with doubly marked BCR-ABL1+/JAK2V617F-mutant cells and, over a 9-year period, progressed into an accelerated phase (AP) and then terminal blast phase (BP). WGS revealed that the diagnostic cells also contained mutations in ASXL1, SEC23B, MAD1L1, and RREB1 as well as 12,000 additional uncommon DNA variants. WGS of endothelial cells generated from circulating precursors revealed many of these were shared with the CML clone. Surprisingly, WGS of induced pluripotent stem cells (iPSCs) derived from the AP cells revealed only six additional coding somatic mutations, despite retention by the hematopoietic progeny of the parental AP cell levels of BCR-ABL1 expression and sensitivity to imatinib and pimozide. Limited analysis of BP cells revealed independent subclonal progression to homozygosity of the MAD1L1 and RREB1 variants. MAD1L1 and SEC23B mutations were also identified in 2 of 101 cases of myeloproliferative neoplasms, but not in 42 healthy subjects. These findings challenge historic concepts of clonal evolution in CML.

Because many of the genes used to produce induced pluripotent stem cells (iPSCs) from somatic cells are either outright established oncogenes, such as c- myc and Klf4 , or potentially related to tumorigenesis in various cancers, both the safety and the risks of tumorigenesis linked to iPSC generation require evaluation. In this work, we generated, by lentivirus-mediated gene transfer of Oct4 , Sox2 , Nanog , and Lin28 , two types of iPSCs from human mesenchymal stem cells and human amniotic fluid–derived cells: fully reprogrammed iPSCs with silencing of the four transgenes and partially reprogrammed iPSCs that still express one or several transgenes. We assessed the behavior of these cells during both their differentiation and proliferation using in vivo teratoma assays in nonobese diabetic mice with severe combined immunodeficiency. In contrast to fully reprogrammed iPSCs, 43% of partially reprogrammed iPSC cases (6 of 14 teratomas) generated major dysplasia and malignant tumors, with yolk sac tumors and embryonal carcinomas positive for α-fetoprotein, cytokeratin AE1/AE3, and CD30. This correlated with the expression of one or several transgenes used for the reprogramming, down-regulation of CDK 1A mRNA (p21/CDKN1A), and up-regulation of antiapoptotic Bcl-2 mRNA. Therefore, the oncogenicity of therapeutically valuable patient-specific iPSC-derived cells should be scrupulously evaluated before they are used for any clinical applications.