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In Asian populations with non-small-cell lung cancer (NSCLC), EGFR mutations are highly prevalent, occurring in roughly half of these patients. Studies have revealed that individuals with EGFR mutation typically fare worse with immunotherapy. In patients who received EGFR tyrosine kinase inhibitor (TKI) treatment followed by anti-PD-1 therapy, poor results were observed. The underlying mechanism remains unclear. We used high-resolution flow cytometry and ELISA to detect the circulating level of small extracellular vesicle (sEV) PD-L1 in NSCLC individuals with EGFR mutations before and after receiving TKIs. The secretion amount of sEV PD-L1 of lung cancer cell lines with EGFR mutations under TKI treatment or not were detected using high-resolution flow cytometry and Western blotting. The results revealed that patients harboring EGFR mutations exhibit increased levels of sEV PD-L1 in circulation, which inversely correlated with the presence of CD8+ T cells in tumor tissues. Furthermore, tumor cells carrying EGFR mutations secrete a higher quantity of PD-L1-positive sEVs. TKI treatment appeared to amplify the levels of PD-L1-positive sEVs in the bloodstream. Mutation-induced and TKI-induced sEVs substantially impaired the functionality of CD8+ T cells. Importantly, our findings indicated that EGFR mutations and TKI therapies promote secretion of PD-L1-positive sEVs via distinct molecular mechanisms, namely the HRS and ALIX pathways, respectively. In conclusion, the increased secretion of PD-L1-positive sEVs, prompted by genetic alterations and TKI administration, may contribute to the limited efficacy of immunotherapy observed in EGFR-mutant patients and patients who have received TKI treatment. [ABSTRACT FROM AUTHOR]

Objective: Small extracellular vesicle (sEV)‐mediated intercellular communication is increasingly the key for the understanding of venous malformations (VMs). This study aims to clarify the detailed changes of sEVs in VMs. Subjects and Methods: Fifteen VM patients without treatment history and twelve healthy donors were enrolled in the study. sEVs were isolated from both fresh lesions and cell supernatant, and were examined by western blotting, nanoparticle tracking analysis and transmission electron microscopy. Western blot analysis, immunohistochemistry and immunofluorescence were adopted to screening candidate regulator of sEV size. Specific inhibitors and siRNA were employed to validate the role of dysregulated p‐AKT/vacuolar protein sorting‐associated protein 4B (VPS4B) signaling on the size of sEVs in endothelial cells. Results: The size of sEVs derived from both VM lesion tissues and cell model was significantly increased. VPS4B, whose expression level was mostly significantly downregulated in VM endothelial cells, was responsible for the size change of sEVs. Targeting abnormal AKT activation corrected the size change of sEVs by recovering the expression level of VPS4B. Conclusion: Downregulated VPS4B in endothelial cells, resulted from abnormally activated AKT signaling, contributed to the increased size of sEVs in VMs. [ABSTRACT FROM AUTHOR]

Continuously recording the dynamic changes of circulating tumor cells (CTCs) is crucial for tumor metastasis. This paper creates a continuous magnetic separation microfluidic chip that enables rapid and continuous in vivo cell detection. The chip shows its potential to study tumor cell circulation in the blood, offering a new platform for studying the cellular mechanism of tumor metastasis. [ABSTRACT FROM AUTHOR]

A 32-year-old male presented with a painless swelling on his nasal dorsum, persisting for over 3 months. He reported a gradual increase in the size of the mass, with no identifiable triggers except occasional skin redness. He denied nosebleeds, rhinorrhea, nasal obstruction, trauma, prior surgery, or spontaneous pain. His medical history revealed gout, managed with colchicine and diclofenac. Despite dietary and pharmaceutical interventions, he continued to have bouts of hyperuricemia, with blood uric acid levels measuring 739 μmol/L. Multiple tophi were evident, especially on the left first metatarsophalangeal joint (Figure 1A). Examination revealed an irregularly shaped, immobile, hard swelling at the nasal radix, measuring 3 cm×2 cm. Computerized tomography (CT) imaging of the nose showed bilateral nasal bone destruction from the lesion. Given its impact on the patient's appearance and his history of gout, the mass was initially diagnosed as unusual gouty tophus. The patient requested surgical removal of the lesion, and the dissection revealed a mass partly encased by a capsule-like connective tissue adherent to the nasal bone. As the lesion damaged the nasal bone, removal of the lesion led to defect of nasal bone. After an extensive rinse of the surgery site, the incision was sutured., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

PD-L1 localized to immunosuppressive small extracellular vesicles (sEV PD-L1) contributes to tumor progression and is associated with resistance to immune-checkpoint blockade (ICB) therapy. Here, by establishing a screening strategy with a combination of tissue microarray (TMA), IHC staining, and measurement of circulating sEV PD-L1, we found that the endosomal sorting complex required for transport (ESCRT) member protein hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) was the key regulator of circulating sEV PD-L1 in head and neck squamous cell carcinoma (HNSCC) patients. Increased HRS expression was found in tumor tissues and positively correlated with elevated circulating sEV PD-L1 in patients with HNSCC. The expression of HRS was also negatively correlated to the infiltration of CD8+ T cells. Knockdown of HRS markedly reduced PD-L1 expression in HNSCC cell-derived sEVs, and these sEVs from HRS knockdown cells showed decreased immunosuppressive effects on CD8+ T cells. Knockout of HRS inhibited tumor growth in immunocompetent mice together with PD-1 blockade. Moreover, a higher HRS expression was associated with a lower response rate to anti-PD-1 therapy in patients with HNSCC. In summary, our study reveals HRS, the core component of ESCRT-0, regulates sEV PD-L1 secretion, and is associated with the response to ICB therapy in patients with HNSCC, suggesting HRS is a promising target to improve cancer immunotherapy., (©2022 American Association for Cancer Research.)