Fig. 1

Systematic screening and validation of miRNAs targeting the KPNA2 gene. A Online prediction software, including starBase, miRTarBase, miRDB, and miRNA Expression Database (GEO accession no. GSE236933, red denotes up-regulation, blue denotes down-regulation), identified 10 miRNAs likely targeting KPNA2 and showing low expression in BCa. B Quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis of miR-26b-5p expression in BCa cell lines (5637, UMUC-3, J82, T24) and normal bladder epithelial cells (SV-HUC-1) demonstrated its regulatory relationship with KPNA2. C The dual luciferase reporter assay confirmed the direct binding relationship between miR-26b-5p and KPNA2. D GEO database microarray data revealed significant downregulation of miR-26b-5p in BCa tissues compared with normal bladder tissues (p = 0.004). E The ROC curve (AUC = 0.706) indicated good specificity in the GEO database. F Tissue microarrays, validated with clinical samples, showed significantly lower miR-26b-5p expression in BCa tissues compared with normal tissues (high expression in dark purple or dark blue, low expression in pink; p < 0.001)