DNA methylation patterns are influenced by Pax3::Foxo1 expression and developmental lineage in rhabdomyosarcoma tumours forming in genetically engineered mouse models.

Rhabdomyosarcoma (RMS) is a family of phenotypically myogenic paediatric cancers consisting of two major subtypes: fusion-positive (FP) RMS, most commonly involving the PAX3::FOXO1 fusion gene, formed by the fusion of paired box 3 (PAX3) and forkhead box O1 (FOXO1) genes, and fusion-negative (FN) RMS, lacking these gene fusions. In humans, DNA methylation patterns distinguish these two subtypes as well as mutation-associated subsets within these subtypes. To investigate the biological factors responsible for these methylation differences, we profiled DNA methylation in RMS tumours derived from genetically engineered mouse models (GEMMs) in which various driver mutations were introduced into different myogenic lineages.

MDM2 functions as a timer reporting the length of mitosis.

Delays in mitosis trigger p53-dependent arrest in G1 of the next cell cycle, thus preventing repeated cycles of chromosome instability and aneuploidy. Here we show that MDM2, the p53 ubiquitin ligase, is a key component of the timer mechanism triggering G1 arrest in response to prolonged mitosis. This timer function arises due to the attenuation of protein synthesis in mitosis.

Aging Selectively Alters PRR and ISG Expression in Endo- and Ecto-Cervical Stromal Fibroblasts From the Human Female Reproductive Tract.

Problem: Aging alters immune function in women and can lead increased risk of infections, particularly in the female reproductive tract (FRT).

Method Of Study: To determine how aging affects innate immune responses in the cervical stroma of the FRT, we isolated endocervical (CX) and ectocervical (ECX) stromal fibroblasts and determine if their expression of multiple pattern recognition receptors (PRRs) and responses to viral stimulation varied with menopause and age.

Results: Constitutive expression of most PRRs did not vary with age or menopausal status in either cell type.

Novel PAX3::MAML3 Fusion Identified in Alveolar Rhabdomyosarcoma, Using DNA Methylation Profiling to Expand the Genetic Spectrum of "Fusion-Positive" Cases.

Alveolar rhabdomyosarcoma (ARMS) with FOXO1 gene rearrangements is an aggressive pediatric rhabdomyosarcoma subtype that is prognostically distinct from embryonal rhabdomyosarcoma and fusion-negative ARMS. Here, we report 2 cases of ARMS with PAX3::MAML3 fusions. The tumors arose in an infant and an adolescent as stage IV metastatic disease (by Children's Oncology Group staging system).