摘要：目的 检测胃癌患者癌组织及相应癌旁组织线粒体 DNA（mtDNA）含量，并探讨 mtDNA 含量变化与胃癌临床病理特征的关系。 方法 纳入 2011~2013 年间 123 例符合要求的胃癌患者癌及癌旁组织，采用 RT-PCR 相对定量的方法检测mtDNA 含量，统计分析 mtDNA 与胃癌临床病理因素关系。 结果 胃癌组织较癌旁组织 mtDNA 相对含量低，并具有统计学差异（P ＜ 0.0001）。但是癌组织 mtDNA 含量的变化与临床病理特征无相关性，如性别、年龄、肿瘤位置、肿瘤分化程度、肿瘤浸润深度、淋巴结转移、临床分期、 Her-2 表达、 Ki-67 表达。此外 , 以癌 / 癌旁（T/N）相对含量的平均数为分界点，将患者分为相对含量高组和相对含量低组，相比之下，相对低 mtDNA 含量更常见于 T1+T2 组（P=0.04）和 Ki-67 阴性组（P=0.015）。 结论 胃癌癌组织 mtDNA 相对含量低于癌旁组织。此外，癌组织的 mtDNA 含量的相对增加与肿瘤浸润深度和 Ki-67 表达相关。认为 mtDNA 含量改变有望作为一种新型胃癌标志物，且其含量的相对增加与肿瘤进展相关。

Abstract: Objective Analyzing the mtDNA copy number in gastric cancer tissues and adjacent non-cancerous tissues, to investigate the relationship betweenmtDNA alteration and the clinicopathological parameters and patient prognosis in gastric cancer.Methods A total of 123 gastric cancer tissues and adjacent non-cancerous tissues were obtained from the tumor bank of Zhongnan Hospital of Wuhan Universitybetween 2011 and 2013. Relative mtDNA copy number was measured in triplicate by a quantitative real-time PCR assay. Using the statistic analysis analyzed the relationship between mtDNA content and clinicopathological features of the gastric cancer. Results The data showed that the majority of the cancer patients had low levels of mtDNA copy number as compared to adjacent non-cancerous tissues (P<0.0001). While there was no association of mtDNA content with the clinicopathological features, such as gender, age, tumor localization, differentiation, tumor invasion, lymph node metastasis,clinical stage, Her-2 expression, Ki-67 status. Additionally, by using the median ratio copy number as the cutoff point, the patients were separated into high and lowcopy number tumor groups, we found thatcompared with high mtDNA content, low mtDNA content was associated with T1+T2 group (P=0.04) and Ki-67negative (P=0.015). Conclusions In this study, the relative mean mtDNA content was lower in gastric cancer tissues than theadjacent non-cancerous tissues. Additionally, we found a strong link between increased mtDNA content and invasion of the tumor and Ki-67 status.We hypothesis that mtDNA copy number can be used as a new biomarker,and increasing the relative mtDNAcontent seems to be linked to the advancement of gastric cancer progression.