活动期肺结核患者外周血miR-29a的表达及其临床意义

目的分析活动期肺结核患者外周血miR-29a的表达情况及其临床意义。方法收集2015年1月至2016年12月绍兴市立医院诊断的45例未经抗结核治疗的活动性肺结核患者(活动组),45例其他肺部疾患者(其他肺疾病组)和45例健康体检者(健康对照组)的外周血,通过实时定量PCR技术检测各组研究对象血清中miR-29a的表达水平并进行ROC曲线分析。采用ELISA法检测各组研究对象血清IFN-γ表达水平;采用流式细胞术测定各组研究对象外周血T细胞亚群水平。分析活动性结核患者血清miR-29a表达水平与IFN-γ以及T细胞亚群水平之间的相关性。结果活动组患者血清miR-29a表达水平均显著高于其他肺疾病组以及健康对照组(t=7.005、4.307,P0.01)。ROC曲线分析表明miR-29a的曲线下面积为0.874,诊断活动性肺结核的敏感度为66.7%,特异度为93.3%。活动组患者血清中IFN-γ的表达水平显著高于其他肺疾病组和健康对照组(t=16.001、14.771,P0.01)。活动组患者外周血CD_3~+、CD_4~+细胞水平以及CD_4~+/CD_8~+比值显著低于其他肺疾病组和健康对照组(t=7.109、5.601,P0.01;t=3.133、4.455,P0.01;t=2.949、2.500,P0.01),而CD+8细胞水平显著高于其他肺疾病组和健康对照组(t=2.375、2.908,P0.01)。活动组患者血浆miR-29a水平与IFN-γ水平呈负相关(r=-0.8542,P0.01)。活动组患者血浆miR-29a水平与外周血CD_3~+、CD_4~+细胞水平以及CD_4~+/CD_8~+比值呈负相关(r=-0.8412、-0.8856、-0.7746,P0.01),同时与CD_8~+细胞水平呈正相关(r=0.8336,P0.01)。结论活动期肺结核患者外周血miR-29a表达水平显著升高,影响患者免疫应答功能,可作为诊断活动期肺结核的临床标志物。     

阿尔茨海默病血清miR-137、miR-138表达与认知功能损害和外周血淋巴细胞PI3K/Akt信号通路的关系研究

摘要 目的：探讨阿尔茨海默病（AD）患者血清微小核糖核酸（miR）-137、miR-138表达与认知功能损害和外周血淋巴细胞磷脂酰肌醇-3激酶/蛋白激酶（PI3K/Akt）信号通路的关系。方法：选取2020年1月至2022年5月青岛大学附属医院神经内科收治的95例AD患者（AD组）,根据临床痴呆评定量表（CDR）评分将患者分为轻度组（1分,35例）、中度组（2分,42例）、重度组（3分,18例）,另选取63例体检健康志愿者为对照组。检测AD组、对照组血清miR-137、miR-138表达水平以及外周血淋巴细胞PI3K/Akt信号通路相关蛋白表达,采用简易智能精神状态检查量表（MMSE）、蒙特利尔认知评估量表（MoCA）评估认知功能。分析血清miR-137、miR-138与MMSE、MoCA评分以及外周血淋巴细胞PI3K、Akt、B淋巴细胞瘤-2基因（Bcl-2）、Bcl-2相关X蛋白基因（Bax）表达的相关性。结果：AD组血清miR-137水平、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达水平及MMSE、MoCA评分低于对照组（P＜0.05）,血清miR-138、外周血淋巴细胞Bax蛋白表达水平高于对照组（P＜0.05）。重度组血清miR-137水平、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达水平及MMSE、MoCA评分低于中度组和轻度组（P＜0.05）,且中度组低于轻度组（P＜0.05）;重度组血清miR-138、外周血淋巴细胞Bax蛋白表达水平高于中度组和轻度组（P＜0.05）,且中度组高于轻度组（P＜0.05）。AD患者血清miR-137水平与MMSE、MoCA评分、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达呈正相关（P＜0.05）,与外周血淋巴细胞Bax蛋白表达呈负相关（P＜0.05）;AD患者血清miR-138水平与MMSE、MoCA评分、外周血淋巴细胞PI3K、Akt、Bcl-2蛋白表达呈负相关（P＜0.05）,与外周血淋巴细胞Bax蛋白表达呈正相关（P＜0.05）。结论：AD患者的血清miR-137表达水平降低、miR-138表达水平增高,与认知功能障碍有关,且miR-137、miR-138可能通过调控PI3K/Akt信号通路参与AD发病过程。     

miR-155-3p对HANK1细胞EAF1 mRNA降解速率及恶性增殖的影响*

目的:探究miR-155-3p对人NK/T细胞淋巴瘤细胞HANK1恶性行为的影响及潜在机制。方法:Targetscan数据库预测miR-155-3p的靶基因,培养对数生长期HANK1细胞,将细胞分为空白组、过表达组、对照组及干扰组,利用细胞转染技术依次转入pENTER-puro空白载体、pENTER-miR-155-3p过表达载体、GV248对照载体、GV248-miR-155-3p siRNA干扰载体。同时放线菌素D(ActD)处理各组细胞,实时荧光定量PCR技术检测各组细胞miR-155-3p、EAF1、β-catenin及c-Myc的表达水平,并分析各组细胞ActD处理后EAF1 mRNA降解速率(n=5),Western blot检测细胞EAF1、β-catenin及c-Myc蛋白表达情况(n=3),CCK-8检测细胞恶性增殖能力变化(n=5)。结果:与空白组相比,过表达组细胞miR-155-3p、β-catenin及c-Myc表达水平显著增高,EAF1表达水平降低且EAF1 mRNA半衰期缩短,细胞恶性增殖能力增强(P均＜0.05);与对照组相比,干扰组细胞miR-155-3p、β-catenin及c-Myc表达水平显著降低,EAF1表达水平升高且EAF1 mRNA半衰期延长,细胞恶性增殖能力降低(P均＜ 0.05)。结论:miR-155-3p可促进EAF1 mRNA降解及HANK1细胞恶性增殖能力。     

过表达miR-155抑制BMP9诱导间充质干细胞C3H10T1/2成骨分化

目的:研究过表达miR-155对BMP9诱导间充质干细胞C3H10T1/2成骨分化的影响。方法:(1)用重组腺病毒Ad-BMP9(BMP9)诱导C3H10T1/2细胞成骨分化,定量PCR(qPCR)检测miR-155的表达,RT-PCR检测Runx2和ALP的表达。(2)miR-155和BMP9共同处理C3H10T1/2细胞,qPCR检测miR-155的表达,ALP活性和染色检测早期成骨能力。(3)miR-155和BMP9共同处理C3H10T1/2细胞,诱导分化14d茜素红S染色检测晚期成骨能力。(4)miR-155和BMP9共同处理C3H10T1/2细胞,qPCR检测成骨分化相关基因Runx2、OSX、COL1A1、ALP、OCN和OPN的表达。(5)miR-155和BMP9共同处理C3H10T1/2细胞,Western blot检测p-Smad1/5/8、OCN和OPN蛋白水平的表达。(6)qPCR和Western blot分别检测HIF1α和VEGF的mRNA表达水平和蛋白质表达水平。(7)应用荧光素酶报告基因对miR-155的靶基因进行筛选和验证。结果:在BMP9诱导C3H10T1/2细胞成骨分化过程中,过表达miR-155降低ALP活性及染色;减少钙盐沉积;成骨分化相关基因Runx2、OSX、COL1A1、ALP、OCN和OPN表达降低;抑制p-Smad1/5/8、OCN和OPN蛋白水平的表达;HIF1α和VEGF的mRNA和蛋白表达水平减少。在对靶基因的检测中,过表达miR-155可以抑制HIF1α蛋白水平的表达,但对其mRNA水平无明显影响。结论:miR-155过表达减弱BMP9诱导间充质干细胞C3H10T1/2成骨分化,可能是通过抑制Smad/BMP信号通路发挥作用,也有可能是通过抑制靶基因HIF1α的表达来发挥作用。     

血清miR-34b-5p、miR-155表达与早产儿急性呼吸窘迫综合征炎症因子和预后的关系分析

摘要 目的：探讨血清微小核糖核酸（miR）-34b-5p、miR-155表达与早产儿急性呼吸窘迫综合征（ARDS）炎症因子和预后的关系。方法：选择2019年2月至2021年3月我院收治的92例ARDS早产儿,根据ARDS病情严重程度将其分为轻度组（31例）、中度组（43例）和重度组（18例）,追踪患儿临床结局,根据院内死亡情况将其分为存活组（51例）和死亡组（41例）。检测所有患儿的血清miR-34b-5p、miR-155表达水平以及白细胞介素-1β（IL-1β）、肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）水平,比较各组间上述指标差异,分析ARDS早产儿血清miR-34b-5p、miR-155表达与炎症因子的相关性以及miR-34b-5p、miR-155预测ARDS早产儿预后的价值。结果：重度组miR-155表达水平及IL-1β、TNF-α、IL-6水平均高于中度组和轻度组,且中度组高于轻度组（P＜0.05）,重度组miR-34b-5p表达水平低于中度组和轻度组,且中度组低于轻度组（P＜0.05）。死亡组miR-155表达水平及IL-1β、TNF-α、IL-6水平高于存活组（P＜0.05）,死亡组miR-34b-5p表达水平低于存活组（P＜0.05）。ARDS早产儿miR-155表达水平与IL-1β、TNF-α、IL-6水平均呈正相关,而miR-34b-5p表达水平与IL-1β、TNF-α、IL-6水平均呈负相关（P＜0.05）。联合miR-34b-5p、miR-155预测ARDS早产儿死亡的曲线下面积（AUC）为0.853,高于两指标单独预测的0.688、0.649。结论：ARDS早产儿血清miR-34b-5p、miR-155表达水平与患儿血清炎症因子水平以及预后有关,可作为ARDS早产儿病情评估以及预后预测的潜在指标。     

系统性红斑狼疮外周血单个核细胞cFLIP—L mRNA和cFLIP—S mRNA表达的研究

目的探讨系统性红斑狼疮（system lupus erythematosus,SLE）患者外周血单个核细胞（peripheral blood monouuclear cells,PBMC）中细胞型Fas相关死亡域样白介素-1β转换酶抑制蛋白（cFLIP）表达的意义。方法应用半定量RT—PCR方法检测38例SLE患者和21名正常人PBMC中cFLIP—L mRNA和cFLIP—S mRNA的表达水平,并与SLE疾病活动指数（SLEDAI）评分进行相关性分析。结果①SLE患者PBMC中cFLIP—L mRNA和cFLIP—S mRNA表达水平均明显高于正常对照组（P〈0．01）;SLE患者活动组cFLIP—L mRNA表达水平显著高于非活动组（P〈0．05）,cFLIP—S mRNA表达水平在SLE患者活动组与非活动组之间没有显著性差异（P〉0．05）。②SLE患者cFLIP—L mRNA表达水平与SLEDAI评分呈正相关（r=0．423,P〈0．01）;而eFLIP—S mRNA表达水平与SLEDAI评分无明显相关性（r=0．270,P〉0．05）。结论cFLIP—L mRNA和cFLIP—S mRNA可能在SLE发病机制中起重要作用。     

miR-155通过促进炎症因子释放参与脓毒症肠道屏障功能障碍的发生发展

摘要 目的：探讨miR-155在脓毒症致肠道功能障碍中的表达及作用。方法：（1）临床实验：以2022年5月至2022年8月入住新疆医科大学第一附属医院重症医学科的脓毒症患者和同期健康体检者为研究对象,根据急性胃肠损伤分级（AGI）将脓毒症患者分为AGI组和非AGI组。根据28 d生存情况分为存活组和死亡组,采用实时荧光定量反转录-聚合酶链反应（qRT-PCR）法前瞻性观察各组外周血miR-155的变化。（2）体内实验：将20只雄性S/D大鼠按照随机数字表法分为假手术组（sham组）和盲肠结扎穿孔术组（CLP组）,采用qRT-PCR及Western blot法检测miR-155、肠道紧密连接蛋白（ZO-1、claudin-1）的表达,ELISA法检测大鼠肠道组织中IL-1β、IL-6、IL-18的表达水平。(3)体外实验：培养人结直肠腺癌细胞（Caco-2）,并分为正常对照组(完全培养基培养48 h)、脂多糖组（完全培养基培养24 h后加入10 μg/mL LPS处理24 h）。采用qRT-PCR检测miR-155的表达。在倒置荧光显微镜下观察细胞形态的变化。采用CCK-8检测细胞活力。采用免疫荧光观察Caco-2细胞中紧密连接蛋白ZO-1分布的变化。并行细胞旁通透性实验,观察两组细胞旁通透性的变化。结果：（1）脓毒症组和健康对照组相比,脓毒症患者外周血miR-155较健康对照组明显升高,差异具有统计学意义（P<0.05）。AGI组患者外周血miR-155表达较非AGI组明显升高,差异具有统计学意义(P<0.05)。脓毒症死亡患者外周血miR-155表达显著升高(P<0.05)。（2）应用CLP模型进行体内动物实验,CLP组大鼠肠道组织miR-155表达较假手术组（sham组）明显升高。CLP组大鼠肠道紧密连接蛋白（ZO-1、claudin-1）较sham组下降,差异具有统 计学意义(P<0.05)。ELISA结果提示,CLP大鼠肠道组织中IL-1β、IL-6、IL-18水平较sham组显著升高（P<0.05）,且肠道组织中miR-155水平与IL-1β、IL-6、IL-18呈正相关（r=0.542,r=0.906,r=868,P<0.05）。（3）与正常对照组相比,经LPS处理后细胞形态破坏、细胞间紧密连接破坏、细胞活力减弱、细胞旁通透性增加。结论：脓毒症发生时伴有肠道屏障功能障碍,miR-155在脓毒症肠道屏障功能障碍中表达升高,并可能通过促进炎症因子的释放参与脓毒症肠道屏障功能障碍的发生发展。miR-155异常表达对脓毒症患者早期肠道功能障碍诊断及预后的评估具有重要价值,可作为脓毒症早期肠道损伤诊断及预后情况的重要指标。     

miR-155 通过p53/p21 调控前列腺癌细胞周期

目的:探讨miR-155对前列腺癌细胞周期的影响及其分子机制。方法:通过转染anti-miR-155抑制前列腺癌DU145和PC-3细胞中miR-155水平后,采用流式细胞术观察细胞周期的变化,western blot和RT-PCR观察p53和p21蛋白及CDK2和cyclin蛋白和m RNA表达的变化。结果:与对照组相比,DU145和PC-3细胞转染anti-miR-155后,G2/M期细胞阻滞,S期细胞数比例显著增加(P0.05),p53和p21蛋白和m RNA表达水平显著增加(P0.01),CDK2和cyclin E蛋白和m RNA表达均显著降低(P0.01)。结论:miR-155可影响人前列腺癌细胞的周期,可能与其调节p53、p21及其下游的CDK2和cyclin E的表达相关。     

miR-550a-3靶向NFIC表达调控肺癌细胞HCC827增殖、迁移和侵袭

[目的]探讨miR-550a-3靶向NFIC表达调控肺癌细胞HCC827增殖、迁移和侵袭作用。[方法]检测40例肺癌患者癌组织和癌旁组织中miR-550a-3和NFIC mRNA表达,并分析NFIC表达与肺癌患者病理特征的相关性。按Lipofectamine 2000方法分别将miR-NC、miR-550a-3 mimics和miR-550a-3inhibitor转染到HCC827细胞,48h后检测细胞增殖、迁移和侵袭情况,同时检测细胞中miR-550a-3和NFIC mRNA表达,并检测细胞中NFIC、E-cadherin和N-cadherin蛋白表达。[结果]肺癌组织中miR-550a-3表达水平(1.83±0.19)高于癌旁组织(1.00±0.15),NFIC mRNA表达水平(0.62±0.14)低于癌旁组织(1.00±0.10)(P<0.05);以miR-550a-3 mRNA均数为标准,将肺癌患者分为高表达组(22例)和低表达组(18例),miR-550a-3与病理类型和TNM分期相关(P<0.05),与年龄、性别、是否吸烟和肿瘤直径不相关(P>0.05)...     

miR-15a 和miR-16-1 模拟物对人骨肉瘤细胞系SOSP-9607 凋亡 和增殖的影响

目的:探讨miR-15a和miR-16-1模拟物对于人骨肉瘤细胞系SOSP-9607凋亡和增殖的影响。方法:将SOSP-9607细胞分为实验组和对照组。实验组分为miR-15a组、miR-16-1组、miR-15a+miR-16-1组。以miR-15a组为例,采用miR-15a模拟物(hsa-miR-15a mimics)上调SOSP-9607细胞内的miR-15a表达量。对照组分为阴性对照组和空白对照组。采用流式细胞仪测定细胞凋亡率,四甲基偶氮唑蓝(MTT)法测定细胞增殖,并计算细胞增殖效率。结果:通过统计学分析,实验组凋亡率与阴性对照组凋亡率相比明显增高(P<0.05);实验组的细胞增殖率明显低于对照组(P<0.05)。结论:上调SOSP-9607细胞内miR-15a和miR-16-1的表达量可促进SOSP-9607细胞的凋亡并抑制其增殖。     

The clinical significance of miR-335, miR-124, miR-218 and miR-484 downregulation in gastric cancer

Gastric cancer (GC) is one of the leading types of malignancy worldwide, particularly in Asian populations. Although the exact molecular mechanism of GC development remains unknown, microRNA (miRNA) has recently been shown to be involved. The current study aims to investigate the expression levels of bioinformatically ranked miRNAs in gastric tissues. Using bioinformatics tools, we prioritized miRNAs thought to be implicated in GC. Furthermore, polyA-qPCR was used to validate bioinformatics findings in 40 GC, 31 normal gastric tissue (NG) and 45 gastric dysplasia (GD) samples. As identified by bioinformatics analysis, miR-335 was shown to be the top-ranked miRNA implicated in GC. Moreover, a significant downregulation of miR-335, miR-124, miR-218 and miR-484 was found in GC and GD compared to NG samples. We found bioinformatics to be an efficient approach to finding candidate miRNAs relevant to GC development. Finally, the findings show that downregulation of miRNAs such as miR-124 and miR-218 in gastric tissue can be a significant indicator for neoplastic transformation.     

Differentially expressed miR-20, miR-21, miR-100, miR-125a and miR-146a as a potential biomarker for prostate cancer

Prostate cancer is the leading cause of death among men worldwide. Deregulation of microRNAs has been reported in many cancers. Expression of microRNAs miR-20a-5p, miR-21-5p, miR-100-5p, miR-125a-5p and miR-146a-5p in tissue blocks of histologically confirmed prostate cancer patients compared with BPH patients, to identify potential microRNA biomarker for prostate cancer. MicroRNA was isolated and expression was quantified by qRT-PCR using Taqman Advanced microRNA assay kits. The interactions between the microRNA:target mRNA were predicted by using bioinformatics tools such as miRwalk and miRTargetlink. The experimentally validated targets were analysed using gprofiler to identify their molecular function, biological process and related pathways. The expression analysis revealed that miR-21 and miR-100 were significantly down-regulated whereas miR-125a was up-regulated in prostate cancer patients. Comparative analysis of the expression levels with tumor grading reveal that miR-100 was significantly down-regulated (p?<?0.05) in high grade tumor, indicating that miR-100 associated with prostate cancer. ROC analysis revealed that combined analysis of down-regulated miRNAs (miR-21 and miR-100) shown AUC of 0.72 (95% CI 0.65–0.79). The combined analysis of all five miRNAs showed AUC of 0.87 (95% CI 0.81–0.92). The targets prediction analysis revealed several validated targets including BCL2, ROCK1, EGFR, PTEN, MTOR, NAIF1 and VEGFA. Our results provide evidence that combined analysis of all the five miRNAs as a panel can significantly improve the prediction level of the presence of prostate cancer and may be used as a potential diagnostic biomarker.

     

Downregulation of miR-31, miR-155, and miR-564 in chronic myeloid leukemia cells

Background/Aims

MicroRNAs (miRNAs) are short non-coding regulatory RNAs that control gene expression and play an important role in cancer development and progression. However, little is known about the role of miRNAs in chronic myeloid leukemia (CML). Our objective is to decipher a miRNA expression signature associated with CML and to determine potential target genes and signaling pathways affected by these signature miRNAs.

Results

Using miRNA microarrays and miRNA real-time PCR we characterized the miRNAs expression profile of CML cell lines and patients in reference to non-CML cell lines and healthy blood. Of all miRNAs tested, miR-31, miR-155, and miR-564 were down-regulated in CML cells. Down-regulation of these miRNAs was dependent on BCR-ABL activity. We next analyzed predicted targets and affected pathways of the deregulated miRNAs. As expected, in K562 cells, the expression of several of these targets was inverted to that of the miRNA putatively regulating them. Reassuringly, the analysis identified CML as the main disease associated with these miRNAs. MAPK, ErbB, mammalian target of rapamycin (mTOR) and vascular endothelial growth factor (VEGF) were the main molecular pathways related with these expression patterns. Utilizing Venn diagrams we found appreciable overlap between the CML-related miRNAs and the signaling pathways-related miRNAs.

Conclusions

The miRNAs identified in this study might offer a pivotal role in CML. Nevertheless, while these data point to a central disease, the precise molecular pathway/s targeted by these miRNAs is variable implying a high level of complexity of miRNA target selection and regulation. These deregulated miRNAs highlight new candidate gene targets allowing for a better understanding of the molecular mechanism underlying the development of CML, and propose possible new avenues for therapeutic treatment.     

The clinical significance of circulating miR-21, miR-142, miR-143, and miR-146a in patients with prostate cancer

BackgroundProstate cancer (PCa) is the most common type of solid tissue cancer among men in western countries. In this study, we determined the levels of circulating miR-21, miR-142, miR-143, miR-146a, and RNU 44 levels as controls for early diagnosis of PCa.MethodsThe circulating miRNA levels in peripheral blood samples from 43 localized PCa patients, 12 metastatic PCa (MET) patients, and a control group of, 42 benign prostate hyperplasia (BPH) patients with a total of 97 volunteers were determined the by PCR method.ResultsNo differences in the DCT values were found among the groups. In PCa and PCaMet groups the expression of miR21 and miR142 were higher compared to the BHP group. No other differences were observed among the other groups. miR21 expression in the PCa group was 6.29 folds upregulated whereas in the PCaMet group 10.84 folds up-regulated. When the total expression of miR142 is evaluated, it showed a positive correlation with mir21 and mir 146 (both p<0.001). Also, the expression of miR146 shows a positive correlation with both miR21 and miR143 (both p<0.001). Expression of miRNAs was found to be an independent diagnostic factor in patients with Gleason score, PSA, and free PSA levels.ConclusionsOur study showed that co-expression of miR21, miR-142, miR-143, and miR-146a and the upregulation of miR-21 resulted in increased prostate carcinoma cell growth. In the PCaMet group, miR21 is the most upregulated of all miRNAs. These markers may provide a novel diagnostic tool to help diagnose PCa with aggressive behavior.     

Identification of miR-17, miR-21, miR-27a,miR-106b and miR-222 as endoplasmic reticulum stress-related potential biomarkers in circulation of patients with atherosclerosis

Molecular Biology Reports - Atherosclerosis and related cardiovascular diseases are among the most common&nbsp;causes of death worldwide. Unfolded protein response, also known as Endoplasmic...     

Circulating microRNAs,miR-939, miR-595, miR-519d and miR-494, Identify Cirrhotic Patients with HCC

The performance of circulating biomarkers for the diagnosis of hepatocellular carcinoma (HCC) is sub-optimal. In this study we tested circulating microRNAs as biomarkers for HCC in cirrhotic patients by performing a two stage study: a discovery phase conducted by microarray and a validation phase performed by qRT-PCR in an independent series of 118 patients. Beside miRNAs emerged from the discovery phase, miR-21, miR-221, miR-519d were also tested in the validation setting on the basis of literary and tissue findings. Deregulated microRNAs were assayed in HCC-derived cells in the intracellular compartment, cell culture supernatant and exosomal fraction. Serum and tissue microRNA levels were compared in 14 patients surgically treated for HCC. From the discovery study, it emerged that seven circulating microRNAs were differentially expressed in cirrhotic patients with and without HCC. In the validation set, miR-939, miR-595 and miR-519d were shown to differentiate cirrhotic patients with and without HCC. MiR-939 and miR-595 are independent factors for HCC. ROC curves of miR-939, miR-595 and miR-519d displayed that AUC was higher than AFP. An exosomal secretion of miR-519d, miR-21, miR-221 and miR-1228 and a correlation between circulating and tissue levels of miR-519d, miR-494 and miR-21 were found in HCC patients. Therefore, we show that circulating microRNAs deserve attention as non-invasive biomarkers in the diagnostic setting of HCC and that exosomal secretion contributes to discharging a subset of microRNAs into the extracellular compartment.