Abstract
Background and objectives MicroRNAs (miRNAs) are small, non-coding RNA molecules that regulate gene expression at the post-transcriptional level and play critical roles in tumour development and progression. Bladder cancer requires reliable molecular biomarkers for diagnosis and prognosis; the roles of certain miRNAs remain insufficiently explored. This study aimed to investigate the expression profiles of miR-22-5p and miR-337-5p in bladder cancer and to evaluate their associations with clinicopathological characteristics. Methods Paired tumour and adjacent non-tumorous bladder tissue samples were collected from 50 patients undergoing transurethral resection of bladder tumour. Quantitative PCR was performed using RNA U6 as the reference gene. Expression differences were analysed, and correlations with clinicopathological features were assessed. Results Both miR-22-5p and miR-337-5p were downregulated in tumour tissues compared to normal tissues. miR-22-5p expression showed a marked reduction in bladder cancer, while miR-337-5p downregulation reached borderline statistical significance. Correlation analyses revealed no association between miR-22-5p expression and clinical variables; however, miR-337-5p expression was significantly correlated with patient age and disease duration. Interpretation and conclusions Altered expression of miR-22-5p and miR-337-5p may contribute to bladder cancer pathogenesis. miR-22-5p appears as a potential tumour suppressor, while miR-337-5p expression is influenced by clinical parameters such as age and disease duration, highlighting their potential roles as prognostic and therapeutic biomarkers.