第一临床医学院知识库

背景与目的  环状RNA（circular RNA）是一种单链闭合环状结构的特殊非编码RNA。环状RNA包括三种类型，单纯由外显子闭合构成的环状结构叫外显子环状RNA，由内含子闭合构成的环状结构为内含子环状RNA，还有一种由外显子和内含子混合形成的闭合环状结构称为外显子-内含子环状RNA（EIciRNAs）。近年来，由于环状RNA功能被不断发现，以及其与肿瘤的相关性研究进展，环状RNA已成为肿瘤领域中的研究热点。然而，有关于环状RNA和胃癌研究的报道却很少。在前期实验中，我们通过基因芯片技术检测环状RNA在14对早期胃癌组织与癌旁组织的表达情况，与癌旁组织相比，总共筛选出10个差异表达的环状RNA，其中有5个环状RNA在早期胃癌组织中表达上调，尤其hsa_circ_0005480在胃癌组织中的表达量显著高于胃癌癌旁组织。我们推测hsa_circ_0005480可能促进胃癌的发生、发展，据此，本实验研究中，我们通过实时荧光定量PCR（qRT-PCR）和琼脂糖凝胶电泳进一步验证hsa_circ_0005480在胃癌组织中的表达水平，并分析其在胃癌组织中表达水平与临床病理特征的关系。进一步探索hsa_circ_0005480在临床上诊断胃癌的价值，为今后诊治胃癌提供新的思路和基础。

方法  在前期实验中，我们通过基因芯片技术筛选出hsa_circ_0005480在早期胃癌组织中的表达量显著上调2.8283倍（P=0.0167）。从外科胃癌切除手术中总共收集了42例配对的胃癌组织及癌旁组织标本，并收集了42例患者的临床病理资料。采用qRT-PCR检测hsa_circ_0005480在42例胃癌组织与阴性对照（癌旁组织）中的表达水平，使用配对t检验分析hsa_circ_0005480在胃癌与癌旁组织中表达水平的差异。采用独立样本t检验分析胃癌组织中hsa_circ_0005480表达水平与患者临床病理特征的关系，并使用受试者工作特征曲线来评估hsa_circ_0005480在临床上诊断胃癌的价值。结果  （1）hsa_circ_0005480表达于胃癌组织中。（2）胃癌组织中hsa_circ_0005480的表达水平高于胃癌癌旁组织（P=0.01）。（3）hsa_circ_0005480的表达水平与胃癌组织的浸润深度有关（P=0.021），而与胃癌患者的性别、年龄、TNM分期、淋巴结转移、肿瘤大小、分化程度等无明显相关性(P﹥0.05)。（4）使用hsa_circ_0005480的表达水平（ΔCT）评估胃癌诊断价值中，受试者工作特征曲线下面积为0.641，P﹤0.05，最佳诊断界值（ΔCT）为6.25，敏感度为88.1%，特异度为45.2%。

结论  hsa_circ_0005480在胃癌组织中表达上调，hsa_circ_0005480可能参与了胃癌的侵袭过程。hsa_circ_0005480对胃癌的诊断具有一定价值。

Backgronund and Objective  Circular RNA (circRNA) is a kind of special noncoding RNA of single closed loop structure. CircRNA includes three types, simply made of the exon closed called exons circular RNA, composed of introns closed circular RNA as introns, there is also a formed by mixing exons and introns closed circular structure called exons - introns circular RNA (EIciRNAs). In recent years, as the circRNA function found, as well as the research progress of circRNA and tumor, circRNA has become a hot spot in the field of tumor. However, few studies of circRNA and gastric cancer have been reported. In the previous experiment, we used gene chip technology to detect the expression of circRNA in 14 paired early gastric cancer tissues and adjacent nontumorous tissues, compared with adjacent nontumorous tissues, a total of 10 different expression circRNA are found in gastric cancer,among which 5 were up-regulated in gastric cancer tissues,especially the expression of hsa_circ_0005480 in early gastric cancer tissues significantly higher than adjacent nontumorous tissues. We speculated hsa_circ_0005480 may promote the occurrence and development of gastric cancer, in this study, expression level of hsa_circ_0005480 was detected in gastric cancer and paired adjacent nontumorous tissues by electrophoresis and real-time quantitative reverse transcription-polymerase chain reactions (qRT-PCR), to analyze the relationship between expression level of hsa_circ_0005480 in gastric cancer tissues and clinicopathological features, to explore the diagnostic value of hsa_circ_0005480 in gastric cancer, it provides new thoughts and theoretical basis to make a diagnosis and give treatment gastric cancer in the future.

Methods  In the previous experiment, we use gene chip technology screen hsa_circ_0005480 expression level higher in early gastric cancer tissues than adjacent nontumorous tissues, it is 2.8283 times(P=0.0167). The 42 paired gastric cancer tissues and adjacent nontumorous tissues were collected From surgical gastric cancer patients, meanwhile, the clinical pathological data of the 42 patients were collected. Expression level of hsa_circ_0005480 was detected in gastric cancer and paired adjacent nontumorous tissues by real-time quantitative reverse transcription-polymerase chain reactions (qRT-PCR), differences in expression level of hsa_circ_0005480 were analyzed by the paired t-test.The relationships between hsa_circ_0005480 expression levels in gastric cancer tissues and clinicopathological features was analyzed by two sample t-test, a receiver operating characteristics (ROC) curve was established to estimate the diagnostic value of hsa_circ_0005480 in gastric cancer.Results  （1）Hsa_circ_0005480 was naturally expressed in gastric cancer tissues. （2）The expression levels of hsa_circ_0005480 was higher in gastric cancer tissues than paired adjacent nontumorous tissues (P=0.01). （3）The expression levels of hsa_circ_0005480 were associated with the invasion of gastric cancer tissues (P=0.021), but we did not found any association between hsa_circ_0005480 expression levels and other clinicopathological factors including gender, age, TNM stage, lymphatic metastasis, tumor size and differentiation degree (P>0.05). （4）Used the expression (ΔCT) of hsa_circ_0005480 in gastric cancer to estimate the diagnostic value, the area under the ROC curve was 0.641, P<0.05, the best cut-off (ΔCT) was 6.25, the sensitivity was 88.1%, the specificity was 45.2%.

Conclusion  Hsa_circ_0005480 was upregulated in gastric cancer tissues, hsa_circ_0005480 may be involved in the invasion of gastric cancer. Hsa_circ_0005480 had certain value for the diagnosis of gastric cancer.