Tomonaga Takeshi, Kume Hideaki
Rinsho Byori. 2015 Mar;63(3):322-7.
Colorectal cancer is the leading cause of cancer-related death in women and third leading cause of death in men. The prognosis worsens when cancer metastasizes to other organs. Thus, there is an urgent need to develop biomarkers for the early diagnosis of metastasis as well as cancer development. Mass spectrometry-based technologies have been applied to the discovery of protein biomarkers, especially in the field of cancer. These results have identified numerous candidate protein biomarkers. Unfortunately, only a few are currently being applied in clinical diagnostics. Recent advances in proteomic technology such as selected/multiple reaction monitoring (SRM/MRM) facilitated the detection and quantitation of specific proteins in complex samples without the need for antibodies. We performed a quantitative proteomic analysis of membrane proteins extracted from colorectal cancer tissues using the iTRAQ shotgun method to discover biomarker candidates, and then extensively validated the biomarker candidate proteins by SRM/MRM. A total of 5,566 proteins were identified in tissue samples obtained from adenoma and cancer with and without metastasis. Differences were observed in the expression of about 400 proteins. Among them, 105 biomarker candidates which were predicted to be membrane proteins and extracellular proteins by gene ontology analysis were quantitated using SRM/MRM. As a result, we could confirm differences in the expressions of 69 of these proteins using the same set of patient samples as discovery experiments, and this was subsequently verified in an independent set of samples. Significant differences were observed in the expression of 44 of these proteins. Moreover, some of the biomarker candidates were detected and quantitated in the serum of colorectal cancer patients. These biomarker candidates are promising diagnostic tools on investigating the development and progression of colorectal cancer.
结直肠癌是女性癌症相关死亡的主要原因，也是男性死亡的第三大原因。当癌症转移至其他器官时，预后会恶化。因此，迫切需要开发用于早期诊断转移以及癌症发展的生物标志物。基于质谱的技术已应用于蛋白质生物标志物的发现，尤其是在癌症领域。这些结果已鉴定出众多候选蛋白质生物标志物。不幸的是，目前只有少数几种应用于临床诊断。蛋白质组学技术的最新进展，如选择/多反应监测（SRM/MRM），有助于在无需抗体的情况下检测和定量复杂样品中的特定蛋白质。我们使用iTRAQ鸟枪法对从结直肠癌组织中提取的膜蛋白进行了定量蛋白质组分析，以发现候选生物标志物，然后通过SRM/MRM对候选生物标志物蛋白进行了广泛验证。在从腺瘤和有无转移的癌症中获得的组织样本中，共鉴定出5566种蛋白质。观察到约400种蛋白质的表达存在差异。其中，通过基因本体分析预测为膜蛋白和细胞外蛋白的105种候选生物标志物，使用SRM/MRM进行了定量。结果，我们可以使用与发现实验相同的患者样本集确认其中69种蛋白质表达的差异，随后在一组独立样本中得到验证。观察到其中44种蛋白质的表达存在显著差异。此外，在结直肠癌患者的血清中检测并定量了一些候选生物标志物。这些候选生物标志物有望成为研究结直肠癌发生和发展的诊断工具。
