Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, Shandong, China.
PLoS One. 2012;7(2):e31868. doi: 10.1371/journal.pone.0031868. Epub 2012 Feb 21.
Colorectal cancer (CRC) is the third most common malignancy in the world. The risk of death is closely correlated to the stage of CRC at the time of primary diagnosis. Therefore, there is a compelling need for the identification of blood biomarkers that can enable early detection of CRC. We used a quantitative proteomic approach with isobaric labeling (iTRAQ) to examine changes in the plasma proteome of 10 patients with CRC compared to healthy volunteers. Enzyme-Linked Immunosorbnent Assay (ELISA) and Western blot were used for further validation. In our quantitative proteomics analysis, we detected 75 human plasma proteins with more than 95% confidence using iTRAQ labeling in conjunction with microQ-TOF MS. 9 up-regulated and 4 down-regulated proteins were observed in the CRC group. The ORM2 level in plasma was confirmed to be significantly elevated in patients suffering from CRC compared with the controls. ORM2 expression in CRC tissues was significantly increased compared with that in corresponding adjacent normal mucous tissues (P<0.001). ITRAQ together with Q-TOF/MS is a sensitive and reproducible technique of quantitative proteomics. Alteration in expression of ORM2 suggests that ORM2 could be used as a potential biomarker in the diagnosis of CRC.
结直肠癌（CRC）是世界上第三大常见恶性肿瘤。死亡风险与原发性诊断时 CRC 的分期密切相关。因此，迫切需要鉴定能够早期检测 CRC 的血液生物标志物。我们使用等重标记（iTRAQ）的定量蛋白质组学方法来比较 10 例 CRC 患者与健康志愿者的血浆蛋白质组变化。采用酶联免疫吸附测定（ELISA）和 Western blot 进行进一步验证。在我们的定量蛋白质组学分析中，我们使用 iTRAQ 标记与 microQ-TOF MS 结合，检测到了 75 种具有超过 95%置信度的人类血浆蛋白。在 CRC 组中观察到 9 种上调蛋白和 4 种下调蛋白。与对照组相比，CRC 患者血浆中的 ORM2 水平被证实显著升高。CRC 组织中的 ORM2 表达明显高于相应的相邻正常粘膜组织（P<0.001）。iTRAQ 与 Q-TOF/MS 相结合是一种敏感且可重复的定量蛋白质组学技术。ORM2 表达的改变表明 ORM2 可作为 CRC 诊断的潜在生物标志物。
