Claudins, a group of membrane proteins involved in the formation of tight junctions, are mainly found in endothelial or epithelial cells. These proteins have attracted much attention in recent years and have been implicated and studied in a multitude of diseases. Claudins not only regulate paracellular transepithelial/transendothelial transport but are also critical for cell growth and differentiation. Not only tissue-specific but the differential expression in malignant tumors is also the focus of claudin-related research. In addition to up- or down-regulation, claudin proteins also undergo delocalization, which plays a vital role in tumor invasion and aggressiveness. Claudin (CLDN)-1 is the most-studied claudin in cancers and to date, its role as either a tumor promoter or suppressor (or both) is not established. In some cancers, lower expression of CLDN-1 is shown to be associated with cancer progression and invasion, while in others, loss of CLDN-1 improves the patient survival. Another topic of discussion regarding the significance of CLDN-1 is its localization (nuclear or cytoplasmic vs perijunctional) in diseased states. This article reviews the evidence regarding CLDN-1 in cancers either as a tumor promoter or suppressor from the literature and we also review the literature regarding the pattern of CLDN-1 distribution in different cancers, focusing on whether this localization is associated with tumor aggressiveness. Furthermore, we utilized expression data from The Cancer Genome Atlas (TCGA) to investigate the association between CLDN-1 expression and overall survival (OS) in different cancer types. We also used TCGA data to compare CLDN-1 expression in normal and tumor tissues. Additionally, a pathway interaction analysis was performed to investigate the interaction of CLDN-1 with other proteins and as a future therapeutic target.

Head and neck squamous cell carcinomas (HNSCCs) are aggressive diseases with a dismal patient prognosis. Despite significant advances in treatment modalities, the five-year survival rate in patients with HNSCC has improved marginally and therefore warrants a comprehensive understanding of the HNSCC biology. Alterations in the cellular and non-cellular components of the HNSCC tumor micro-environment (TME) play a critical role in regulating many hallmarks of cancer development including evasion of apoptosis, activation of invasion, metastasis, angiogenesis, response to therapy, immune escape mechanisms, deregulation of energetics, and therefore the development of an overall aggressive HNSCC phenotype. Cytokines and chemokines are small secretory proteins produced by neoplastic or stromal cells, controlling complex and dynamic cell–cell interactions in the TME to regulate many cancer hallmarks. This review summarizes the current understanding of the complex cytokine/chemokine networks in the HNSCC TME, their role in activating diverse signaling pathways and promoting tumor progression, metastasis, and therapeutic resistance development.

Post-traumatic stress disorder (PTSD) is a highly disabling condition, increasingly recognized as both a disorder of mental health and social burden, but also as an anxiety disorder characterized by fear, stress, and negative alterations in mood. PTSD is associated with structural, metabolic, and molecular changes in several brain regions and the neural circuitry. Brain areas implicated in the traumatic stress response include the amygdala, hippocampus, and prefrontal cortex, which play an essential role in memory function. Abnormalities in these brain areas are hypothesized to underlie symptoms of PTSD and other stress-related psychiatric disorders. Conventional methods of studying PTSD have proven to be insufficient for diagnosis, measurement of treatment efficacy, and monitoring disease progression, and currently, there is no diagnostic biomarker available for PTSD. A deep understanding of cutting-edge neuroimaging genetic approaches is necessary for the development of novel therapeutics and biomarkers to better diagnose and treat the disorder. A current goal is to understand the gene pathways that are associated with PTSD, and how those genes act on the fear/stress circuitry to mediate risk vs. resilience for PTSD. This review article explains the rationale and practical utility of neuroimaging genetics in PTSD and how the resulting information can aid the diagnosis and clinical management of patients with PTSD.

Background and Clinical Significance: Methyltransferase-like protein 5 (METTL5) is a conserved RNA methyltransferase responsible for catalyzing the N6-methyladenosine (m6A) modification of 18S ribosomal RNA, a process critical for ribosome biogenesis and translational regulation. Biallelic variants in METTL5 have been linked to autosomal recessive intellectual developmental disorder-72 (MRT72), typically presenting with microcephaly, intellectual disability, and speech delay. However, the association between METTL5 and isolated attention-deficit/hyperactivity disorder (ADHD) remains underexplored. Case Presentation: We report a 14-year-old Qatari female, born to consanguineous parents, who presented with microcephaly, speech delay, learning difficulties, and inattentive-type ADHD. Trio-based whole-genome sequencing identified a novel homozygous METTL5 variant (c.617G > A; p. Arg206Gln), with both parent’s heterozygous carriers. The variant is extremely rare (gnomAD MAF: 0.0000175) and predicted to be deleterious (CADD: 23.7; SIFT: damaging; PolyPhen-2: probably damaging). Structural modeling localized the change within the SAM-dependent catalytic domain, predicting protein destabilization (ΔΔG = +1.8 kcal/mol). The affected residue is highly conserved (ConSurf score: 8), and protein–protein interaction analysis linked METTL5 with METTL14, METTL16, and ZCCHC4, key regulators of rRNA methylation. Conclusions: In silico evidence suggests that the p. Arg206Gln variant disrupts METTL5 function, likely contributing to the observed neurodevelopmental phenotype, including ADHD. This expands the clinical spectrum of METTL5-related disorders and supports its inclusion in neurodevelopmental gene panels.

Background/Objectives: Adolescents with anorexia nervosa (AN) face substantial medical and psychiatric risk during hospitalization. We examined predictors of length of stay (LOS), cardiovascular recovery, refeeding safety, and psychiatric comorbidity in a consecutive pediatric cohort at a national tertiary center. Methods: Retrospective cohort of 68 consecutively admitted adolescents (91.2% female; mean age 14.2 ± 1.8 years, range 8–17; 85.3% restricting type) admitted between January 2017 and May 2025. A structured nutritional rehabilitation protocol (1000–1200 kcal/day, escalating by 200 kcal/day every 48 h to 2500–3000 kcal/day) was implemented with daily serum electrolyte monitoring. Statistical analyses included paired tests, Spearman correlations, multivariable regression of log-transformed LOS, and partial correlations controlling for the admission BMI z-score. Results: Nutritional and cardiovascular parameters improved from admission to discharge. Mean supine heart rate (HR) increased by 28.4 bpm (95% CI 25.0–31.8; p < 0.001), and bradycardia prevalence (HR < 50 bpm) improved from 39.7% to 1.5%. Lower admission BMI z-score was associated with longer LOS; each 1-unit higher BMI z-score was associated with an 18.9% shorter LOS in adjusted log-LOS regression (p = 0.003). Exploratory analyses of HR recovery suggested that the magnitude of HR improvement was more closely associated with baseline BMI z-score and baseline supine HR than with caloric escalation. Systematic electrolyte monitoring documented no hypophosphatemia requiring intervention and no refeeding syndrome. Documented mental health comorbidities or clinically significant symptom clusters were present in 82.4% of patients. Conclusions: In this adolescent anorexia nervosa cohort, structured inpatient nutritional rehabilitation was associated with substantial cardiovascular and nutritional improvement. Baseline nutritional status was associated with hospital course and cardiovascular response, while LOS should be interpreted as a composite outcome influenced by nutritional severity, discharge criteria, mental health needs, and family readiness. The absence of refeeding complications is reassuring and suggests that the protocol was metabolically safe under systematic electrolyte monitoring in this specialized tertiary setting.