使用p53與Caspase-3蛋白作為大腸癌預後指標之研究

A Study of Using p53 and Caspase-3 Proteins as Prognosis Indicators in Colorectal Cancer

祝振興(Chen-Hsing Chu)

指導教授 ： 周芬碧

中山醫學大學/醫學院/生化暨生物科技研究所/碩士(2009年)

https://doi.org/10.6834/CSMU.2009.00100

摘要

局部性大腸直腸癌（CRC）病患主要治療方法為手術切除，但其中仍有高達百分之30至70的局部復發率。此篇論文主要研究局部晚期大腸直腸癌患者接受術前化學放射治療後，觀察其細胞凋亡情形，以評估是否可以p53及Caspase-3蛋白做為病患的預後指標。臨床上選擇II或III期的大腸直腸癌患者，在病患進行診斷切片及在接受術前化放療後手術切除腫瘤時收集檢體。將檢體的部分做病理的檢驗及病理分期。以免疫組織化學染色方法觀察p53與Caspase-3蛋白於檢體中表現情形，比較兩者之表現模式是否有相關性。結果顯示：檢體中p53的表現相異性頗大，在診斷檢體可觀察到無表現(20%)、少量表現(12%)及顯著的表現(68%)，其中有表現p53之診斷檢體在細胞中之表現位置比例分別為細胞核(5%)、細胞質(15%)及兩者都有(80%)；在接受術前化放療後之手術檢體可觀察到p53無表現(52%)、少量表現(24%)及顯著的表現(24%)，其中有表現p53之手術檢體在細胞中之表現位置比例分別為細胞核(42%)、細胞質(16%)及兩者都有(42%)。所有檢體中Caspase-3之表現較p53為弱，區域亦較小，在診斷檢體可觀察到無表現(52%)、少量表現(8%)及顯著的表現(40%)，其中有表現Caspase-3之診斷檢體在細胞中之表現位置比例分別為細胞核(5%)、細胞質(5%)及兩者都有(90%)；在接受術前化放療後之手術檢體則無觀察到Caspase-3表現(100%)。以連續切片觀察，同時表現p53與Caspase-3的診斷檢體可觀察到兩者表現位置有重疊(80%)及相反(20%)的情形。觀察同一病例可發現多數患者(62%)接受術前化放療後，手術檢體較診斷檢體之p53的表現顯著減少，在Caspase-3的表現方面也有半數以上的患者(56%)表現顯著減少，有些患者(31%)可共同觀察到此二蛋白的表現減少。有部分病患(45%)在接受術前化放療後，癌期症狀可觀察到有減緩的現象，其中又有患者(36%)診斷檢體之p53有顯著表現，而在接受術前化放療後，手術檢體之p53表現明顯減少。接受術前化放療後，在患者手術檢體上無觀察到Caspase-3表現。在此研究可觀察到術前化放療對大腸直腸癌患者，有使其病理趨緩的情形，且其p53表現亦有明顯減少，Caspase-3蛋白的表現甚至觀察到為完全消失。p53與Caspase-3的表現對於術前接受化放療病患具有其特定性，推估可以觀察患者之癌期變化，配合比較其p53與Caspase-3蛋白在術前化放療前後之表現量，作為預後評估之指標。

關鍵字

大腸直腸癌 ； 術前化放療 ； 免疫組織化學染色 ； p53 ； Caspase-3

並列摘要

Surgery is the main curative modality in patients with localized colorectal cancer (CRC), but there is still about 30 to 70 % probability that local relapses occurred. The aim of the present work was to observe cell apoptosis of those patients with localized colorectal cancer who took preoperative chemoradiotherapy and evaluated the possibility that use p53 and Caspase-3 proteins as prognosis indicators on patients. Patients with clinical stage II or III colorectal cancer were selected for sample collection at the time of diagnosis or surgery. The pathology of cancer cell was recorded. Immunohistochemistry was performed to observe the expression of p53 and Caspase-3 proteins in tissue sections. Compared the p53 protein with Caspase-3 protein and analyzed the connections between these two proteins. Our data showed that the expressions of p53 were various differences between the tissue sections. In diagnosis sections, it was observed no detectable p53 (20%), few expressed p53 (12%) and significant expressed p53 (68%). For those diagnosis sections expressed p53, some were detected expression in nucleus only (5%), some were detected expression in cytoplasm only (15%) and some were detected in both nucleus and cytoplasm (80%). In surgery sections, which are collected after preoperative chemoradiotherapy, there were observed no detectable p53 (52%), few expressed p53 (24%) and significant expressed p53 (24%). For those surgery sections expressed p53, some were detected expression in nucleus (42%), some were detected expression in cytoplasm (16%) and some were detected in both nucleus and cytoplasm (42%). Compared with p53, the expressions of Caspase-3 in all sections were weaker and detected in smaller area. In diagnosis sections, there were observed no detectable Caspase-3 (52%), few expressed Caspase-3 (8%) and significant expressed Caspase-3 (40%). For those diagnosis sections expressed Caspase-3, some were detected expression in nucleus (5%), some were detected expression in cytoplasm (5%) and some were detected in both nucleus and cytoplasm (90%). In surgery sections, there was observed no detectable Caspase-3 at all (100%). Serial sections were showed that p53 and Caspase-3 proteins expressed at the same location in diagnosis sections (80%) and some of them expressed p53 and Caspase-3 proteins at the different location instead (20%). Compared diagnosis section with surgery section both of them were from the same patient, lots of the patients (62%) were observed that surgery sections had less expression of p53 than that in diagnosis sections and more than half of patients (56%) were observed that surgery sections had less expression of Caspase-3 than that in diagnosis sections. Some of those patients (31%) were observed that surgery sections had less expression both of p53 and Caspase-3 than that in diagnosis sections. It was observed that the pathology of colorectal cancer on patients (45%) who took preoperative chemoradiotherapy were downstaged. Some of them (36%) were detected significant expression of p53 in diagnosis sections and the expression of p53 was reduced significantly after preoperative chemoradiotherapy. There was no detectable Caspase-3 in surgery sections from patients after preoperative chemoradiotherapy. At the present work, we observed that the pathology on patients with colorectal cancer was downstaged, the expression of p53 was reduced significantly and the expression of Caspase-3 was disappeared after preoperative chemoradiotherapy. Expressions of p53 and Caspase-3 are specific to the patients who were treated with preoperative chemoradiotherapy. It was suggested that p53 and Caspase-3 can be the prognosis indicators by comparing the expressions of these two proteins with the stage of colorectal cancer before and after preoperative chemoradiotherapy.

並列關鍵字

colorectal cancer ； preoperative chemoradiotherapy ； immunohistochemistry ； p53 ； Caspase-3

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