Plasma MiR-320, MiR-let-7e And Mir-21as Novel Potential Biomarker For Retinoblastoma Detection

Background:Retinoblastoma is the most common intraocular malignant tumor in children. About more than9000cases are increased in the whole world every year. At present, the survival rates of RB in developed countries has been to90%, while only55%in China. The cause of this difference is mainly about the early diagnosis of RBs in developing countries lag behind other nations, so many RBs were diagnosed when the tumor had infringed on the eye socket or intracranial. Therefore, looking for a convenient, fast, sensitive and specific molecular biomarker to improve the early diagnostic rate of RB patients seems so importment in our country.Objective:Our study aimed to investigate whether the expression of candidate miRNAs(miR-373, miR-503, miR-320, miR-let-7e, miR-492, miR-498and miR-21) show some differences between the plasma of RB patients and healthy controls by real-time quantitative polymerase chain reaction (qRT-PCR). We also discuss the relationship of plasma miRNAs and the clinical characteristics of RB patients, and evaluate the value of plasma miRNAs to distinguish RB patients from healthy controls.Methods:(1) To collect the plasma samples of15RB patients without any treatment and15age-matched healthy controls first. Using qRT-PCR to test the expression level of the candidate miRNAs(miR-373, miR-503, miR-320, miR-let-7e, miR-492, miR-498and miR-21).(2) To validate the expression of screened miRNAs in plasma of another50RB patients without any treatment and50age-matched healthy controls by qRT-PCR.(3) The availability of detecting RB by plasma miRNAs and miRNAs matched with NSE was analyzed by receiver operating characteristic (ROC) curve and area under the ROC curve(AUC). To further explore the association of plasma miRNAs and RB clinical characteristics.Results:(1) Plasma miR-320, miR-let-7e and miR-21were down-regulated in15patient samples according to the preliminary screening results.(2) The expression of plasma miR-320, miR-let-7e and miR-21were also reduced in another50RB patients, especially for miR-320.(3) The expression of plasma miRNAs were not significant different between the different ages, genders, unilateral or bilateral and tumor stages. The AUCs for miR-320, miR-let-7e and miR-21were0.660(95%CI:0.558-0.752, P=0.0036),0.587(95%CI:0.484-0.684, P=0.1280) and0.548(95%CI:0.446-0.648, P=0.4100), respectively. The sensitivity for miR-320; miR-let-7e and miR-21were58%,76%and46%separately, and specificity for them were74%,42%,72%, respectively. AUCs for miR-320, miR-let-7e and miR-21combined with NSE respectively were0.996(95%CI:0.957-1.000, P<0.0001),0.991(95%CI:0.948-1.000, P<0.0001) and0.993(95%CI:0.950-1.000, P<0.0001), separately. The sensitivity for combined classifiers were98%,94%,94%, respectively, and specificity for them were98%,100%,100%, respectively.Conclutions:(1) Plasma miR-320, miR-let-7e and miR-21might participate in the pathogenesis and development of RB according to their low expression level in RB patients.(2) Plasma miR-320, miR-let-7e and miR-21shown no siginificant differences among different ages, genders, unilateral or bilateral, and tumor stages in RB patients. Maybe miR-320, miR-let-7e and miR-21were involved in the early stage of pathogenesis of retinoblastoma.(3) Plasma miR-320shown the largest AUC among the three miRNAs, it also own the largest AUC when the three miRNAs combined with NSE respectively. We think miR-320shows some importance in RB diagnose and can be regarded as novel diagnose biomarker.