Objective:To investigate the clinical, cytomorphology, immunocytochemical and molecular features of metastatic melanoma in serosal cavity effusion.Methods:Cytological specimens of 14 patients with melanoma in the chest and abdomen were collected from 2017 to 2023, at the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. SOX10, S-100 protein, PRAME, BRAF V600E, HMB45, and Melan A were detected by immunocytochemical methods. Fourteen cases were tested for routine antibody combinations, including Claudin4, HEG1, Calretinin, CD68, etc. Four of the patients had biopsy or surgical samples of metastatic solid lesions of primary sites, and further next-generation sequencing (NGS) or amplification refractory mutation system (ARMS)-PCR molecular test was performed. In addition, 30 cases of serosal effusion samples were collected as control groups (10 cases of benign mesothelial cell reactive hyperplasia, 10 cases of mesothelioma, and 10 cases of metastatic lung adenocarcinoma).Results:Among the 14 cases of melanoma, there were 7 males and 7 females, with ages ranging from 35 to 86 years, and an average age of 57 years, there 10 cases aged ≥50 years. The tumor cells in the serosal effusion varied in morphology and degree of atypia. SOX10 was positive in all 14 cases (14/14), S-100 protein was positive in 10 cases (10/14), PRAME was positive in 12 cases (12/14), BRAF V600E was positive in 10 cases (10/14), HMB45 was positive in 12 cases (12/14), and Melan A was positive in 13 cases (13/14). In 4 patients with histological correlation, the cytological and histological expression of SOX10, BRAF V600E, and PRAME was positive in all 4 cases (4/4); S-100 protein was positive in 2 cases (2/4); and HMB45 and Melan A were positive in 3 cases (3/4). Using NGS or ARMS-PCR, missense mutations of BRAF V600E were detected in all 4 patients; TERT promoter mutations was detected in 1 case; and CDKN2A terminating mutations and MSI1 deletion mutations were detected in the other case. SOX10, S-100, HMB45, Melan A, PRAME and BRAF V600E were all negative in 30 control samples of serosal cavity effusion.Conclusion:By observing the morphology of tumor cells, immunocytochemical test of several combination markers, especially the expression of SOX10, BRAF V600E and PRAME, can help to improve the positive diagnosis rate of melanoma in serous cavity effusion.

Catalase is widely used in the food, medical, and textile industries. It possesses exceptional properties including high catalytic efficiency, high specificity, and environmental friendliness. Free catalase cannot be recycled and reused in industry, resulting in a costly industrial biotransformation process if catalase is used as a core ingredient. Developing a simple, mild, cost-effective, and environmentally friendly approach to immobilize catalase is anticipated to improve its utilization efficiency and enzymatic performance. In this study, the catalase KatA derived from Bacillus subtilis 168 was expressed in Escherichia coli. Following separation and purification, the purified enzyme was prepared as an immobilized enzyme in the form of enzyme-inorganic hybrid nanoflowers, and the enzymatic properties were investigated. The results indicated that the purified KatA was obtained through a three-step procedure that included ethanol precipitation, DEAE anion exchange chromatography, and hydrophobic chromatography. Then, by optimizing the process parameters, a novel KatA/Ca₃(PO₄)₂ hybrid nanoflower was developed. The optimum reaction temperature of the free KatA was determined to be 35 ℃, the optimum reaction temperature of KatA/Ca₃(PO₄)₂ hybrid nanoflowers was 30-35 ℃, and the optimum reaction pH of both was 11.0. The free KatA and KatA/Ca₃(PO₄)₂ hybrid nanoflowers exhibited excellent stability at pH 4.0-11.0 and 25-50 ℃. The KatA/Ca₃(PO₄)₂ hybrid nanoflowers demonstrated increased storage stability than that of the free KatA, maintaining 82% of the original enzymatic activity after 14 d of storage at 4 ℃, whereas the free KatA has only 50% of the original enzymatic activity. In addition, after 5 catalytic reactions, the nanoflower still maintained 55% of its initial enzymatic activity, indicating that it has good operational stability. The K_m of the free KatA to the substrate hydrogen peroxide was (8.80±0.42) mmol/L, and the k_cat/K_m was (13 151.53± 299.19) L/(mmol·s). The K_m of the KatA/Ca₃(PO₄)₂ hybrid nanoflowers was (32.75±2.96) mmol/L, and the k_cat/K_m was (4 550.67±107.51) L/(mmol·s). Compared to the free KatA, the affinity of KatA/Ca₃(PO₄)₂ hybrid nanoflowers to the substrate hydrogen peroxide was decreased, and the catalytic efficiency was also decreased. In summary, this study developed KatA/Ca₃(PO₄)₂ hybrid nanoflowers using Ca²⁺ as a self-assembly inducer, which enhanced the enzymatic properties and will facilitate the environmentally friendly preparation and widespread application of immobilized catalase.
Catalase ; Nanostructures/chemistry* ; Hydrogen Peroxide/metabolism* ; Enzymes, Immobilized/chemistry* ; Catalysis