目的：探讨肝细胞肝癌（HCC）患者血清microRNAlet-7a（let-7a）水平的变化及其对HCC的诊断价值。方法：用qRT-PCR检测60例HCC患者及46例健康体检者血清let-7a的表达，分析血清let-7a水平与HCC的临床病理因素的关系，用受试者工作曲线（ROC）分析其对HCC的诊断效能。结果：HCC患者血清let-7a相对表达量明显低于健康对照组人群（0.538 vs. 1.571，P<0.05）；HCC患者血清let-7a水平达与癌栓形成有关（P<0.05），与性别、年龄、HBV感染、肝硬化、肿瘤直径、肿瘤个数、淋巴结转移、TNM分期、淋巴结转移、病理分级、AFP水平均无关（均P>0.05）；以0.529为let-7a诊断HCC的最佳临界值，其灵敏度为79%，特异度为71%，曲线下面积（AUC）为0.77（95% CI=0.624~0.839）；联合检测血清let-7a与AFP，诊断HCC的灵敏度为83%，特异性为97%，AUC为0.92（95% CI=0.866~0.987）。结论：HCC患者血清let-7a水平降低，let-7a可能成为诊断HCC的新的分子标志物，联合AFP检测可提高对HCC的诊断的准确性。
Alteration of serum microRNAlet-7a level in patients with hepatocellular carcinoma and its significance
Objective: To investigate the alteration of serum microRNAlet-7a (let-7a) level in patients with hepatocellular carcinoma (HCC) and its diagnostic value for HCC. Methods: The let-7a expressions in 60 HCC patients and 46 healthy subjects undergoing health maintenance examination were measured by qRT-PCR. And then the relations of serum let-7a level with clinicopathologic factors of HCC patients were analyzed and the diagnostic efficacy of let-7a for HCC was determined by using a receiver operating characteristic curve (ROC). Results: The relative expression level of serum let-7a in HCC patients was significantly lower than that in healthy population (0.538 vs. 1.571, P<0.05). The serum let-7a level was significantly associated with the formation of tumor emboli (P<0.05), but was irrelevant to all other studied factors that included sex, age, HBV infection, cirrhosis, tumor diameter, tumor number, lymph node metastasis, TNM stage, pathological grade and AFP level (all P>0.05). At an optimal cut-off value of 0.529 of let-7a for diagnosis of HCC, the sensitivity was 79%, the specificity was 71% and the area under the curve (AUC) was 0.77 (95% CI=0.624–0.839) respectively; in combined detection of serum let-7a and AFP for diagnosis of HCC, the sensitivity was 83%, the specificity was 97% and the AUC was 0.92 (95% CI=0.866–0.987), respectively. Conclusion: The serum let-7a level is decreased in HCC patients, which may be potentially used as a new molecular marker for diagnosis of HCC, and its diagnostic efficacy for HCC can be enhanced by combination detection of AFP.