Hu Ying, Han Haibo, Wang Yixue, Song Lijie, Cheng Xiaojing, Xing Xiaofang, Dong Bin, Wang Xiaohong, Chen Meng, Zhang Lianhai, Ji Jiafu
1 Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of BioBank, Peking University Cancer Hospital and Institute , Beijing, China .
2 Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Division of Gastrointestinal Cancer Translational Research Laboratory, Peking University Cancer Hospital and Institute , Beijing, China .
Biopreserv Biobank. 2017 Jun;15(3):241-247. doi: 10.1089/bio.2016.0035. Epub 2017 Feb 7.
Comparative analysis of RNA expression profiles between cancer and adjacent noncancerous tissues is an important part of cancer research. High-quality RNA is essential for consistent, reliable results, especially for identification of cancer biomarkers. However, the impact of freeze-thaw cycles on the quality of RNA both in gastrointestinal cancer and paired adjacent tissues is still unclear.
To investigate the influence of freeze-thaw cycles on RNA integrity and overall histomorphology of gastrointestinal cancer and paired adjacent noncancerous tissues.
Gastrointestinal cancer and matched adjacent noncancerous tissues were frozen and thawed twice before extracting RNA. Total RNA in each sample was extracted with TRIzol reagents and the RNA integrity was assessed by RNA integrity number (RIN) on an Agilent Bioanalyzer. Light microscopy was then used to assess tissue composition and morphology.
RIN values for all samples tended to decrease in correlation with the frequency of freeze-thawing. With an RIN cutoff value of 6, RNA extracted from pancreatic cancer tissues was not qualified after the first freeze-thaw cycle. Moreover, all RNA extracted from adjacent noncancerous tissues had nonqualifying RIN scores after the first freeze-thaw cycle, except for liver tissues. Microscopically, all samples displayed qualified tissue morphology regardless of freeze-thaw cycle frequency.
Freeze-thawing affects the RNA integrity, but not the tissue morphology of gastrointestinal cancer and paired adjacent noncancerous tissues. Furthermore, the RNA extracted from adjacent noncancerous tissues is more easily degraded than that in cancer tissues.
癌症组织与相邻正常组织之间RNA表达谱的比较分析是癌症研究的重要组成部分。高质量的RNA对于获得一致、可靠的结果至关重要，尤其是在癌症生物标志物的鉴定方面。然而，冻融循环对胃肠道癌及其配对的相邻组织中RNA质量的影响仍不清楚。
探讨冻融循环对胃肠道癌及其配对的相邻正常组织RNA完整性和整体组织形态学的影响。
胃肠道癌组织及其配对的相邻正常组织在提取RNA前进行两次冻融。每个样本的总RNA用TRIzol试剂提取，RNA完整性通过安捷伦生物分析仪上的RNA完整性数值（RIN）进行评估。然后用光学显微镜评估组织组成和形态。
所有样本的RIN值均随着冻融频率的增加而呈下降趋势。当RIN临界值为6时，胰腺癌组织在第一次冻融循环后提取的RNA即不合格。此外，除肝脏组织外，所有配对的相邻正常组织在第一次冻融循环后提取的RNA的RIN评分均不合格。在显微镜下，无论冻融循环频率如何，所有样本的组织形态均合格。
冻融循环影响胃肠道癌及其配对的相邻正常组织的RNA完整性，但不影响其组织形态。此外，配对的相邻正常组织提取的RNA比癌组织中的RNA更容易降解。
