Decreased Expression Levels Of PIWIL2, PIWIL3 and PIWIL4 Are Associated with Poor Prognosis and Worse Survival in...

Bladder cancer (BC) remains one of the most prevalent and recurrent malignancies worldwide. Identification of early biomarkers and prognostic indicators is vital for improving diagnostic accuracy and therapeutic outcomes. PIWI-interacting RNA pathway proteins (PIWILs), known regulators of gene silencing and genome stability, have emerged as potential biomarkers in various cancers. This study evaluates the expression patterns of PIWIL1-4 in BC patients and investigates their prognostic value.

Tumor and adjacent tissues were collected from 220 BC patients, along with urine samples from both patients and 70 healthy controls. Total RNA was extracted, followed by cDNA synthesis and real-time PCR for PIWIL1-4. Protein expression of PIWIL2 was evaluated by immunohistochemistry. Clinical data, including staging and histopathological features, were analyzed. In silico analysis (cBioPortal, miRNet) was performed to assess PIWIL gene variants and miRNA associations. Receiver operating characteristic (ROC) curves, logistic regression, and survival analysis were conducted for diagnostic and prognostic assessments.

Expression of all four PIWILs was significantly downregulated in both tissue and urine samples of BC patients compared to controls (p < 0.001). ROC analysis showed high sensitivity and specificity for PIWILs in distinguishing BC from controls (AUC ≥ 0.927). Logistic regression confirmed their diagnostic and prognostic relevance (p < 0.001). PIWIL2, PIWIL3, and PIWIL4 were significantly associated with tumor recurrence (p ≤ 0.01), while all four PIWILs correlated with patient survival. Immunohistochemical analysis of PIWIL2 supported its expression relevance. In silico findings revealed a 7% structural variant frequency for PIWIL2 and functional associations with tumor suppressor miRNAs.

PIWIL1-4, particularly PIWIL2, are significantly downregulated in BC and hold promise as non-invasive diagnostic and prognostic biomarkers. Their expression correlates with recurrence and survival, suggesting clinical utility for improving bladder cancer management. Further studies are recommended to validate these findings in larger cohorts.