Development of novel biomarkers in cancer: Detection of circulating miR-141 as a potential prognostic marker for prostate cancer

Prostate cancer (CAP) is the most common epithelial malignancy and the second leading cause of cancer deaths in American men. The identification of predictive and prognostic biomarkers in CAP patients is critical for improving clinical outcomes. Although the measurement of prostate-specific antigen (PSA) and radiographic studies are clinically approved to predict response to therapy, these tests can oftentimes prove to be inadequate in certain patients. Thus, it is important to discover new biomarkers to improve chances of survivability. We and others have shown that longitudinal measurements of circulating tumor cells (CTC) and lactate dehydrogenase (LDH) may aid in predicting response to therapy. More recently, levels of microRNA (miRNA) have been implicated in disease processes such as cancer. Specifically, the expression of human miRNA miR-141 has been found to be elevated in the plasma of CAP patients. In our study, we have measured the levels of miR-141 in 21 CAP patients and compared it with other clinical markers (CTC, LDH, and PSA). We longitudinally examined these markers alone and in combination in relationship to the patient’s clinical course and response to therapy. Our aim was to determine if miR-141 has the potential to be a putative marker for the prognosis of a patient’s response to therapy.;For this retrospective study, plasma from 21 CAP patients were collected at different time points corresponding to treatment regimen or follow-up appointments. Levels of miR-141 in plasma were measured using quantitative RT-PCR and compared to temporal changes in miR-141, CTC, LDH, and PSA levels. Using PSA as the standard marker in monitoring CAP, correlation coefficients were determined for each biomarker’s capability in predicting clinical outcomes. Our results indicate that there is a strong correlation between a patient’s clinical characteristics and the plasma levels of miR-141. With further testing, we suggest that miR-141 has the potential to be a marker for the prognosis of CAP. We find that miR-141 is largely concordant with the other conventional markers and establish that miR-141 is a relevant biomarker worthy of further investigation.