| 摘要: | 胃癌是世界盛行的癌症之一，於世界癌症發生率的排名中位居第4位，死亡率位居第2位，而在台灣2010年胃癌仍位居國人十大癌症死因的第六名。由於胃癌初期症狀與胃炎、胃或十二指腸潰瘍等胃病相似，加上症狀表現並不一定為持續型，可能一陣子才發作一次，因此很容易被忽視，早期發現與早期診斷胃癌相關的血漿或血清生物標誌物是迫切需要的。目前臨床上常使用的腫瘤標記為CEA、CA19-9及CA72-4，但特異性及靈敏度不高是其缺點。
銅藍蛋白(Ceruloplasmin) ，是血液中最主要的銅結合蛋白，在鐵質的代謝上也扮演了重要的角色。在臨床上最常使用於威爾森氏症 (Wilson's disease) 的診斷，威爾森氏症是體內銅含量過高的一種疾病，銅藍蛋白在銅缺乏時數值會降低，且在急性發炎反應時數值會升高。有文獻探討Ceruloplasmin在胃癌的表現量並用來當作診斷工具，但比較少去探究轉譯後修飾的部份，本實驗中主要探討Ceruloplasmin在胃癌患者血漿中轉譯後修飾的表現，以期找到有意義的轉譯後修飾位點並能發展為有利的診斷工具。
本實驗中，我們以血漿為樣本，將胃癌病患與其性別年齡配對之健康血漿檢體，利用一維SDS-PAGE與西方墨點法觀察Ceruloplasmin在血漿中蛋白質的表現量；再利用膠體內水解(In-Gel digestion)將要測定的蛋白質分離出來，並結合奈米級液相層析串連質譜儀(nano-LC/MS/MS)進行分析，已達到鑑定血漿中微量蛋白質量的變化與不同種類的轉譯後修飾。在本次報告中，我們在胃癌血漿中發現Ceruloplasmin蛋白質的表現在西方墨點法上並無明顯差異，但在轉譯後修飾方面發現了兩個新的修飾，分別是Hydroxylation(Asp-77)、Methylation-1(Arg-1031)，其中Hydroxylation修飾的差異達5倍之多，P值也達到0.002有很好的顯著差異性。
這些結果顯示，在胃癌血漿中新發現Ceruloplasmin的兩個轉譯後修飾，可做為胃癌的生物標記。
Gastric cancer is one of the world prevailing cancer, ranked four in the world rankings of the incidence of cancer, in mortality among the two. Gastric cancer still among the sixth in the top ten causes of death of cancer in Taiwan 2010. Early symptoms of gastric cancer with gastritis and other stomach disease are similar. But symptoms are not necessarily persistent, so it is easily overlooked. It is found that with early diagnosis in gastric cancer associated plasma or serum biomarker is very important. Currently, the major biomarkers of gastric cancer are CEA, CA 19-9 and CA 72-4 in clinical. However, the specificity and sensitivity of those markers are not good .
Ceruloplasmin is the major copper -carrying protein in the blood, and in addition plays a role in iron metabolism. The most commonly used in the clinical diagnosis of Wilson's disease, Wilson's disease is high levels of copper in the body of a disease, ceruloplasmin copper deficiency when the value will be lower, and the value in the acute inflammatory reaction will rise. Until now, some research have explored the protein level of Ceruloplasmin in the plasma of gastric cancer, but few researches show the post-translational modification (PTM) of Ceruloplasmin in gastric cancers.
In this study, we use plasma samples and proteomic approaches such as western blot and nano-LC/MS/MS to analyze the plasma samples from normal and cancer groups, in order to achieve the identification of plasma trace protein changes in the quality of the different types of translational modification of gastric cancer patients. In this report,We identified in the plasma ceruloplasmin protein expression in Western blot was no significant difference, but PTM data showed that there were two PTMs in gastric cancer, including Hydroxylation(Asp-77)、Methylation-1(Arg-1031). There was significance of those PTMs expression between the cancer group and normal
group, p=0.02. These results indicate that two PTM in ceruloplasmin maybe a marker for the evaluation of patients with gastric cancer. |
