Comparison of Circulating MicroRNA 141 to Circulating Tumor Cells, Lactate Dehydrogenase, and Prostate-Specific Antigen for Determining Treatment Response in Patients With Metastatic Prostate Cancer

For prostate cancer (CaP), the measurement of prostate-specific antigen (PSA) and radiographic studies do not adequately predict response to therapy and survival, and, therefore, new relevant biomarkers are needed. We and other researchers have shown that longitudinal measurements of PSA, circulating tumor cells (CTC), and lactate dehydrogenase (LDH) may aid in predicting response to therapy. Results of recent studies have determined that circulating microRNA (miRNA) miR-141 is detected in plasma of patients with CaP. We, therefore, compared the temporal changes of miR-141 with the levels of CTC, LDH, and PSA in 21 patients with CaP, and longitudinally examined these markers alone or in combinations to determine the utility of miR-141 in the predicting a patient's clinical course and response to therapy. Levels of miR-141 in plasma of 21 patients with CaP were measured by using quantitative reverse transcription–polymerase chain reaction. A total of 35 intervals were assessed. Directional changes (increasing or decreasing) in PSA, CTC, and miR-141 had sensitivity in predicting clinical outcome (progression vs. nonprogressing) of 78.9%. Logistic regression modeling of the probability of clinical progression demonstrates that miR-141 levels predicted clinical outcomes with an odds ratio of at least 8.3. miR-141 also had the highest correlation with temporal changes of PSA with a correlation of R = 0.77 (P < .001). In this retrospective study, miR-141 demonstrated a similar ability to predict clinical progression when compared with other clinically validated biomarkers. Furthermore, miR-141 demonstrated high correlation with changes of the other biomarkers.