[Association between expression of plasma miRNA and the risk of childhood acute lymphocytic leukemia].

Objective: To investigate the characteristics of distribution and expression profiles of plasma miRNA in childhood acute lymphocytic leukemia (cALL) patients; the association between cALL incidence risk and plasma miRNA levels; the feasibility of plasma miRNA serving as cALL diagnostic biomarker. Methods: A total of 111 pairs of newly diagnosed cALL patients and patients with fractures were collected from Shenzhen Children's Hospital, China, between January 2015 and November 2016. Age and sex of the cases and controls were 1∶ 1 matched and LNA(TM) miRNA microarray was performed using 4 pairs of cALL and controls selected from the sample population. The expression level of miRNA was validated by real time quantitative PCR. Conditional logistic regression analysis was applied to evaluate the association between miRNA expression levels and the incidence risk of cALL. The receiver operating characteristic curve (ROC) and reclassification analysis were conducted to assess the feasibility of miRNAs serving as biomarkers for cALL. Results: A total of 204 differentially expressed miRNA were screened out and let-7f-5p, miR-5100, miR-25-3p and miR-3654 were selected for validation identified according to the inclusion criteria. The expression levels of let-7f-5p, miR-5100 and miR-25-3p in the cALL patients were significantly lower than those of the controls (P<0.01). After adjusting for confounding factors, 3 miRNAs remained significantly associated with the risk of cALL (OR and 95%CI were 0.84 (0.76-0.92), 0.81 (0.73-0.90) and 0.81 (0.74-0.89), respectively. Results from both the ROC analysis and reclassification analysis showed that introduction of one or more miRNA to traditional risk factors improved the area under the curve (P<0.05) and provided additional values to diagnosis (P<0.01). Conclusion: The expression levels of let-7f-5p, miR-5100 and miR-25-3p were significantly associated with the incidence rate of cALL, and these miRNAs might serve as promising biomarkers for cALL.