Background: Studies have shown that miRNA (miR) can be stably detected in serum, and aberrant expression of various miRNAs has shown diagnostic value in non-small cell lung cancer (NSCLC) patients. However, the role of miRNA in the context of prognosis has not been extensively investigated. Our previous study reported that miR-22, miR-125b, and miR-15b in serum had potential for use as tumor markers for auxiliary diagnosing of NSCLC. Therefore, the objective of this study was to detect the levels of miR-22, miR-125b, and miR-15b in serum from NSCLC patients and explore the potential prognostic significance of the three selected miRNAs.
Methods: The relative expression of miR-22, miR-125b, and miR-15b in 74 patients with advanced NSCLC in pre- and post-chemotherapy were detected by real-time quantitative polymerase chain reaction.
Results: Serum level of miR-125b significantly decreased after chemotherapy (p < 0.05) and the levels of miR-15b significantly increased (p < 0.01), while there was no change in the level of serum miR-22 (Z = 0.716, p > 0.05). Compared with pre-chemotherapy, serum miR-125b expression in advanced NSCLC patients of responders (CR + PR) were significantly decreased post-chemotherapy (p < 0.05); serum miR-15b expression in advanced NSCLC patients of responders (CR + PR) were increased (p < 0.01). The chemotherapy sensitivity of advanced NSCLC patients with high expression of miR-125b was lower than that of NSCLC patients with low expression (p < 0.05). The chemotherapy sensitivity of advanced NSCLC patients with high expression of miR-15b was higher than that of NSCLC patients with low expression (p < 0.05). High levels of serum miR-125b and low levels of serum miR-15b were related to poor overall survival (p < 0.05).
Conclusions: The serum levels of miR-125b and miR-15b in advanced NSCLC patients were changed pre- and post-chemotherapy and these changes were associated with chemotherapeutic response. Serum miR-125b and miR-15b have certain potential clinical value for chemotherapeutic response in advanced NSCLC. The serum levels of miR-125b and miR-15b in patients with advanced NSCLC before treatment may be used to estimate the overall survival.