中国高发区肝细胞癌p53基因热点突变的规律性

目的 研究同发区肝细胞癌（ＨＣＣ）Ｐ５３基因２４９密码子高频度突变的规律性，为探寻癌及基于Ｐ５３的基因和免疫治疗提供依据。方法 用巢工ＰＣＲ结合测序和限制性片段长度多态（ＲＦＬＰ）分析的方法，研究１９９４－１９９７年收集的９７例启东和２２便北京的肝细胞癌标本中，Ｐ５３基因２４９密码子的突变率及突变的基因型。用免疫组化法研究癌及癌周细胞中Ｐ５３蛋白的表达程度。 １９９４－１９９７年，启东肝细胞癌中，

Characteristics of high frequency 249 codon mutation of p53 gene in hepatocellular carcinoma in prevalent area of China

Objective To study the characteristic features of an unique hotspot missense mutation of the 249 codon of p53 gene demonstrated in human hepato-cellular carcinoma(HCC) in a region of high(Qidong) and low(Beijing) exposure to both hepatitis B virus (HBV) and aflatoxin B1 (AFB1) in China. Methods Surgical samples from 97 HCC from Qidong and 22 from Beijing, China, collected in 1994 through 1997, were studied. The 249 codon mutation of p53 gene was detected by PCR followed by HaeIII RFLP analysis and DNA sequencing. Intracellular p53 protein level was determined by immunohistochemical staining. Results High mutation rate of 249 codon of p53 gene was consistently found in recent years, with an average of 53.6% (52/97). No such mutation was identified in 22 Beijing HCC collected in the same time period. The genotype of p53 249 codon mutants which showed heterozygous profile was identified to be homozygous in nature following tumor tissue enrichment. Of 21 HCC shown to have 249 codon mutation, 20 exhibited high intranuclear accumulation of p53 protein. p53 protein staining was negative in the surrounding noncancerous hepatic tissue. Conclusion The high frequency of homozygous mutation of the 249 codon of p53 gene accompanied with p53 protein accumulation provides important enlightenment in the understanding of hepatocarcinogenesis and clinical application of gene therapy and/or immunotherapy for HCC.