Low Expression of CLEC2B Indicates Poor Prognosis in Melanoma

BACKGROUND: Melanoma is a highly malignant skin tumor with a poor prognosis. Identification of novel biomarkers might potentially reveal the underlying mechanisms of melanoma progression. METHODS: We demonstrated the relationship between pan-cancer CLEC2B expression and melanoma samples in The Cancer Genome Atlas (TCGA) database. Next, the Kaplan-Meier plot and Cox regression analysis determined the prognostic value of CLEC2B in melanoma. Biological pathway enrichment was screened by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA), enabling the correlation analysis between the immune infiltration level and CLEC2B expression in melanoma. Our final claim was validated using qPCR, immunohistochemistry, Western blot, cell colony formation assays, ethynyldeoxyuridine (Edu) analysis, and cell Invasion assays. RESULTS: Our study revealed that the high CLEC2B expression correlates with poor overall survival of melanoma patients. Moreover, a low expression of CLEC2B was found in the A375 cell line. In addition, CLEC2B has significant prognostic value in melanoma diagnosis, with an AUC of 0.896. Prognostic analysis showed the low expression of CLEC2B to be independently associated with melanoma patients. Moreover, the expression of CLEC2B was significantly correlated with B cells, eosinophils, macrophages, neutrophils, NK cells, T helper cells, Tregs, Th1 cells, Th17 cells, and Th2 cells. PCR and immunohistochemistry indicated CLEC2B to be significantly downregulated in melanoma. The cell colony formation assay showed CLEC2B knockout increased the proliferation of A375 cells. CONCLUSION: Our study established low levels of CLEC2B to be poor prognostic markers, enabling immunosuppressive cell infiltration in melanoma.