Chain Features and Their Influence on the Thermal Stability of Poly(propylene‐co‐1‐nonene) Copolymers

The thermal stability of several isotactic polypropylenes and propylene‐co‐1‐nonene copolymers is assessed under nitrogen by means of thermogravimetric analysis (TGA). The samples involve wide ranges of molecular weight, isotactic average length, and 1‐nonene content, in order to perform a comprehensive analysis of the effect that chain features exert on the apparent activation energy (E_a), in the initial stages of the molten state degradation. The degradation process correlates with chain mobility and, accordingly, with chain features that are linked to. Thus, microstructure and chain size are found to play a key role. In fact, isotactic average length of propylene sequences and molecular weight are driving factors in the E_a required for main chain thermal scission.     

Comprehensive analysis of isolated der(1;7)(q10;p10) in a large international homogenous cohort of patients with myelodysplastic syndromes

The karyotype is a strong independent prognostic factor in myelodysplastic syndromes (MDS). Since the implementation of the new comprehensive cytogenetic scoring system for MDS, chromosome 7 anomalies are no longer generally assigned to poor risk features but are thoroughly separated. However, der(1;7)(q10;p10), hereinafter der(1;7), is merged into the group labeled “any other single” and belongs to the intermediate risk group, just by definition due to lack of adequate clinical data. The aim of our international collaborative was to clarify the “real” prognostic impact of der(1;7) on a homogenous and well‐documented data base. We performed detailed analysis of 63 MDS patients with isolated der(1;7) constituting the largest cohort hitherto reported. Furthermore, clinical data are compared with those of patients with isolated del(7q) and isolated monosomy 7. Median overall survival (OS) of patients with der(1;7) is 26 months (hazard ratio (HR) 0.91 for del(7q) vs der(1;7) and 2.53 for monosomy 7 vs der(1;7)). The der(1;7) is associated with profound thrombocytopenia most probably causing the reduced OS which is in striking contrast to the low risk for AML transformation (HR 3.89 for del(7q) vs der(1;7) and 5.88 for monosomy 7 vs der(1;7)). Molecular karyotyping indicates that der(1;7) is generated in a single step during mitosis and that a chromosomal imbalance rather than a single disrupted gene accounts for malignancy. Thus, the current cytogenetic scoring system assigning isolated der(1;7) to the intermediate risk group is now confirmed by a sufficient data set.     

Genomic instability in fragile sites—still adding the pieces

Common fragile sites (CFSs) are specific genomic regions in normal chromosomes that exhibit genomic instability under DNA replication stress. As replication stress is an early feature of cancer development, CFSs are involved in the signature of genomic instability found in malignant tumors. The landscape of CFSs is tissue‐specific and differs under different replication stress inducers. Nevertheless, the features underlying CFS sensitivity to replication stress are shared. Here, we review the events generating replication stress and discuss the unique characteristics of CFS regions and the cellular responses aimed to stabilizing these regions.     

Early detection of the PAX3‐FOXO1 fusion gene in circulating tumor‐derived DNA in a case of alveolar rhabdomyosarcoma

Cell‐free DNA (cfDNA), which are small DNA fragments in blood derived from dead cells including tumor cells, could serve as useful biomarkers and provide valuable genetic information about the tumors. cfDNA is now used for the genetic analysis of several types of cancers, as a surrogate for tumor biopsy, designated as “liquid biopsy.” Rhabdomyosarcoma (RMS), the most frequent soft tissue tumor in childhood, can arise in any part of the body, and radiological imaging is the only available method for estimating the tumor burden, because no useful specific biological markers are present in the blood. Because tumor volume is one of the determinants of treatment response and outcome, early detection at diagnosis as well as relapse is essential for improving the treatment outcome. A 15‐year‐old male patient was diagnosed with alveolar RMS of prostate origin with bone marrow invasion. The PAX3‐FOXO1 fusion was identified in the tumor cells in the bone marrow. After the diagnosis, cfDNA was serially collected to detect the PAX3‐FOXO1 fusion sequence as a tumor marker. cfDNA could be an appropriate source for detecting the fusion gene; assays using cfDNA have proved to be useful for the early detection of tumor progression/recurrence. Additionally, the fusion gene dosage estimated by quantitative polymerase chain reaction reflected the tumor volume during the course of the treatment. We suggest that for fusion gene‐positive RMSs, and other soft tissue tumors, the fusion sequence should be used for monitoring the tumor burden in the body to determine the diagnosis and treatment options for the patients.     

Array‐based profiling of the lymphoma cell DNA methylome does not unequivocally distinguish primary lymphomas of the central nervous system from non‐CNS diffuse large B‐cell lymphomas

Primary lymphomas of the central nervous system (PCNSL) are diffuse large B‐cell lymphomas (DLBCLs) confined to the central nervous system (CNS). We here performed array‐based DNA methylation analyses of 26 PCNSL and 78 DLBCL and validated our findings in an independent dataset. We identified 2847 CpGs differentially methylated between PCNSL and non‐CNS‐DLBCL. Neither a supervised analysis using these CpGs nor application of 3 CpG classifiers selected for class separation unambiguously separated PCNSL from non‐CNS‐DLBCL. Remarkably, 6/78 non‐CNS‐DLBCL consistently segregated with PCNSL, which displayed molecular features typical for PCNSL. Our findings suggest that a subset of non‐CNS‐DLBCL exists which molecularly resembles PCNSL.     

Emerging hepatitis E virus compared with hepatitis A virus: A new sanitary challenge

Hepatitis A (HAV) and E (HEV) viruses are able to cause liver disease in humans. Among the five classical hepatotropic viruses, they are mainly transmitted via the fecal‐oral route. Historically, many similarities have thus been described between them according to their incidence and their pathogenicity, especially in countries with poor sanitary conditions. However, recent advances have provided new insights, and the gap is widening between them. Indeed, while HAV infection incidence tends to decrease in developed countries along with public health improvement, HEV is currently considered as an underdiagnosed emerging pathogen. HEV autochthonous infections are increasingly observed and are mainly associated with zoonotic transmissions. Extra hepatic signs resulting in neurological or renal impairments have also been reported for HEV, as well as a chronic carrier state in immunocompromised patients, arguing in favor of differential pathogenesis between those two viruses. Recent molecular tools have allowed studies of viral genome variability and investigation of links between viral plasticity and clinical evolution. The identification of key functional mutations in viral genomes may improve the knowledge of their clinical impact and is analyzed in depth in the present review.