Atypical neurofibromas (aNF) are peripheral nerve sheath tumors (PNSTs) histologically defined by cytologic atypia, hypercellularity, loss of neurofibroma architecture, and/or increased mitotic activity. aNF often have a heterozygous loss of CDKN2A/B in addition to homozygous NF1 loss. On MRI, aNF frequently appear as distinct nodular lesions, grow faster than plexiform neurofibromas, and have increased avidity on fluorodeoxyglucose positron emission tomography. At least some aNF are considered to be at greater risk for transformation to highly aggressive malignant PNSTs. We have observed that some PNSTs demonstrate a discrepancy between histological, clinical, and genomic criteria, where a PNST without histologically concerning findings may have clinical and imaging features concerning aNF and CDKN2A/B loss. This case series highlights this discrepancy and suggests the inclusion of CDKN2A/B loss to define aNF, along with clinical and imaging findings, to determine the potential for malignant transformation, and to select appropriate clinical management.

Aim: Barth syndrome (BTHS) is a rare X-linked genetic disease in which mitochondrial oxidative phosphorylation is impaired due to a mutation in the TAFAZZIN gene. The protein kinase C delta (PKCδ) signalosome exists as a high molecular weight complex in mitochondria and controls mitochondrial oxidative phosphorylation.

Method: Here, we examined PKCδ levels in mitochondria of aged-matched control and BTHS patient B lymphoblasts and its association with a higher molecular weight complex in mitochondria.

Result: Immunoblot analysis of blue-native polyacrylamide gel electrophoresis mitochondrial fractions revealed an increase in total PKCδ protein expression in BTHS lymphoblasts compared to controls. In contrast, PKCδ associated with a higher molecular weight complex was markedly reduced in BTHS patient B lymphoblasts compared to controls. Given the decrease in PKCδ associated with a higher molecular weight complex in mitochondria, we examined the uptake of creatine, a compound whose utilization is enhanced upon high energy demand. Creatine uptake was markedly elevated in BTHS lymphoblasts compared to controls.

Conclusion: We hypothesize that reduced PKCδ within this higher molecular weight complex in mitochondria may contribute to the bioenergetic defects observed in BTHS lymphoblasts and that enhanced creatine uptake may serve as one of several compensatory mechanisms for the defective mitochondrial oxidative phosphorylation observed in these cells.

The field of RNA-based therapeutics is rapidly evolving and targeting non-coding RNAs (ncRNAs) associated with disease is becoming increasingly feasible. MicroRNAs (miRNAs) are a class of small ncRNAs (sncRNAs) and the first anti-miRNA drugs, e.g., Miravirsen and Cobomarsen, have successfully completed phase II clinical trials. Long ncRNAs (lncRNAs) are another class of ncRNAs that are commonly dysregulated in disease. Thus, they hold potential as putative therapeutic targets or agents. LncRNAs can function through a variety of mechanisms, including as guide, scaffold or decoy molecules, and understanding of these actions is critical to devising effective targeting strategies. LncRNA expression can be modulated with small interfering RNAs (siRNAs), antisense oligonucleotides (ASOs), CRISPR-Cas9, or small molecule inhibitors. These approaches have been employed to target a number of lncRNAs and tested in animal models of disease, including targeting ANRIL for non-small cell lung cancer and H19 for pancreatitis. However, there are currently no clinical trials registered in the ClinicalTrials.gov database that target lncRNAs as a therapeutic intervention. In order to translate lncRNA targeting into clinical use, several limitations must be overcome, such as potential toxicity and off-target effects. Overall, while significant progress has been made in the field, further development is required before the clinical application of the first therapeutics targeting lncRNAs. In this review, we discuss recent advances in our understanding of the mechanisms of action of lncRNAs that present avenues for clinical therapeutic targeting and consider off-target effects as a limiting factor in their application.

Prostate cancer remains the most commonly diagnosed and the second leading cause of cancer-related deaths in men in the United States. The neoplastic transformation of prostate epithelia, concomitant with modulations in the stromal compartment, known as reactive stromal response, is critical for the growth, development, and progression of prostate cancer. Reactive stroma typifies an emergent response to disrupted tissue homeostasis commonly observed in wound repair and pathological conditions such as cancer. Despite the significance of reactive stroma in prostate cancer pathobiology, our understanding of the ontogeny, phenotypic and functional heterogeneity, and reactive stromal regulation of the immune microenvironment in prostate cancer remains limited. Traditionally characterized to have an immunologically "cold" tumor microenvironment, prostate cancer presents significant challenges for advancing immunotherapy compared to other solid tumors. This review explores the detrimental role of reactive stroma in prostate cancer, particularly its immunomodulatory function. Understanding the molecular characteristics and dynamic transcriptional program of the reactive stromal populations in tandem with tumor progression could offer insights into enhancing immunotherapy efficacy against prostate cancer.

The review article “Transcription regulation by long non-coding RNAs: mechanisms and disease relevance” by Jorge Ferrer and Nadya Dimitrova, published in Nature Reviews Molecular Cell Biology, explores the complex roles of long non-coding RNAs (lncRNAs) in gene transcription regulation. The authors discuss various mechanisms by which lncRNAs influence transcription, including their functions as cis-regulatory elements, transcription stabilizers, and scaffolds for regulatory complexes. The review also highlights the potential of lncRNAs in disease contexts and their therapeutic applications. However, it is essential to consider the potential limitations in current lncRNA research.