Upregulation of miR-32 in tissue and plasma and its association with PTEN expression in colorectal cancer

Early detection of colorectal cancer (CRC) is critical for improving patient outcomes. MicroRNAs (miRNAs) function as post-transcriptional regulators and have emerged as potential minimally invasive diagnostic biomarkers. Although miR-32 has been implicated in tumor progression in several malignancies, its expression pattern in CRC tissue and plasma and its association with PTEN expression require further clarification.

Expression levels of miR-32 and PTEN were measured using quantitative real-time PCR (qRT-PCR) in tumor tissues, adjacent normal tissues, and plasma samples from 55 CRC patients and plasma samples from 55 age and sex matched healthy controls.

MiR-32 expression was significantly upregulated in CRC tissues and plasma samples, whereas PTEN expression was significantly reduced in tumor tissues (P < 0.001). ROC curve analysis demonstrated strong diagnostic performance of miR-32 in tissue (AUC = 0.942) and good performance in plasma (AUC = 0.846). An inverse association between miR-32 and PTEN expression was observed. Higher miR-32 levels were also associated with advanced tumor stage.

This is the first report of concurrent miR-32 upregulation and PTEN downregulation in both CRC tissue and plasma. MiR-32 may represent a potential non-invasive biomarker candidate for CRC detection and disease stratification. However, these findings are observational and require validation in larger, multicenter cohorts and functional studies before clinical application.