大肠癌细胞p53基因突变与细胞凋亡及细胞倍性的关系

目的　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 Ｐ Ｃ Ｒ Ｓ Ｓ Ｃ Ｐ（ 单链构象多态性） 检测ｐ５３ 基因突变，用流式细胞仪 Ｆａｃｓｃａｎ 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

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.