了解p53基因突变、细胞倍性、细胞凋亡三者的关系，探讨突变型p53基因在肿瘤发生中的作用机制。方法　采用PCR-SSCP(单链构象多态性)检测p53基因突变，用流式细胞仪Facscan检测大肠癌细胞染色体倍性、凋亡率及其在细胞周期各相中的分布情况。结果　大肠癌标本p53基因突变率为50%；其中突变组肿瘤细胞凋亡率(22.11%)明显低于未突变组细胞凋亡率(40.57%)，(P＜0.05)；突变组异倍体细胞百分率(占76.9%)明显高于未突变组(占46.2%)，(P＜0.05)；异倍体肿瘤细胞凋亡率为34.0%，二倍体肿瘤细胞凋亡率为40.7%，二者差异无显著性(P＞0.05)。结论　p53基因突变使肿瘤细胞凋亡率下降，进而促进肿瘤发生、发展。p53基因突变多见于异倍体细胞，细胞凋亡率与细胞倍性无关。

Relationship between p53 gene mutation of colorectal cancer cell, apoptosis and cell ploidy

OU Qishui,SHEN Zhongyi,LU Peihua,et al.

　　(Shanghai Institute of Immunology,Shanghai Second Medical University,Shanghai 200025)

　　【Abstract】Objective To study the relationship among p53 gene mutation, apoptosis and cell ploidy and explore the role that mutated p53 gene plays in the tumorigenesis.Methods p53 gene mutations were detected by PCR-SSCP (single strand conformation polymorphism). Cell ploidy, the rate of apoptosis of tumor cells and cell distribution in each cell phase were detected by flow cytometry.Results The p53 gene mutation rate of colorectal cancer was 50%. The rate of apoptosis of tumor cells having mutation of p53 gene (22.11%) was much lower than that having no p53 mutation (40.57%, P＜0.05). Heteroploid cells had been found in 10/13 tumor samples with p53 gene mutation and 6/13 samples without p53 mutation (P＜0.05). The rate of apoptosis had no difference between the heteroploid cases and diploid cases.Conclusion Mutation of p53 gene decreases the apoptosis rate of colorectal cancer cells and promote tumorigenesis. Cell ploidy had a link with p53 gene mutation, but no link with cell apoptosis.

　　【Key words】 p53 Apoptosis Cell ploidy Gene mutation

　　我们对p53基因突变与大肠癌发生发展的关系，尤其是p53基因与新鲜大肠癌细胞凋亡的关系进行研究，现将结果报道如下。

　　材料与方法

　　1. 标本来源　39例标本均由上海瑞金医院外科提供，其中正常对照组9例(包括癌旁正常组织7例，正常人外周血淋巴细胞2例)；大肠腺瘤4例；大肠癌标本26例，其中未转移组(Duke's A/B期)17例，转移组(Duke's C/D期)9例。其中女性23例，男性16例，年龄24～88岁。

　　2. 标本处理　取2cm×2cm大小的新鲜肿瘤块，用胶原酶消化法收集肿瘤细胞［1］。将细胞分成二部分，一部分细胞按常规方法抽提DNA并配制终浓度为0.1μg/L的应用液于-20℃保存，另取至少3×105个细胞留作下述处理。正常人外周血淋巴细胞用Ficoll分离得到。正常大肠粘膜对照取自远离癌组织的大肠。

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