胃癌p53基因突变与微卫星DNA不稳定性关系的研究

目的 探讨术前不同分期的胃癌ｐ５３基因突变与微卫星ＤＮＡ不稳定性（ｍｉｃｒｏｓａｔｅｌｌｉｔｅ ｉｎｓｔａｂｉｌｉｔｙ，ＭＳＩ）的变化及其相互关系。方法 应用超声内境（ｅｎｄｏｓｃｏｐｉｃ ｕｌｔｒａｓｏｎｏｇｒａｐｈｙ，ＥＵＳ）对７３例胃癌患者行术前分期，同时采用银染ＰＣＲ－ＳＳＣＰ方法检测仙镜活检组织标本ｐ５３基因突变及ＭＳＩ。结果 ｐ５３基因总突变率为５４．８％；Ｔ３期（６４．３％）和Ｔ４期

Study on the p53 gene mutation and microsatellite instability of gastric carcinoma

Objective To observe the relationship between p53 gene mutation and microsatellite instability (MSI) of the preoperative staging of gastric carcinoma by endoscopic ultrasonography(EUS). Methods A total of 73 cases of gastric carcinoma were taken for the preoperative staging with EUS.Silver staining PCR SSCP method was used to detect mutations in exons 5,6,7,8 of p53 gene and MSI at 4 loci on chromosomes 2,5,17 in the 73 paraffin embedded biospy specimens, and the relationship between them was studied further.Results The overall mutated rate of p53 gene was 54.8%, with 6.8%, 15 1%, 19 2% and 13.7% in exons 5 to 8, respectively. Analysis of the relation of the mutation with the preoperative staging by EUS showed that it was significantly higher in T3(64.3%) and T4(67.9%) than in T1(0) or T2(25.0%)(P<0.05), and it was 67.6% in cases with lymph node metastasis, which was significantly higher than that without metastasis (41.7%)(P<0.05). The overall detective rate of MSI was 37.0%. The detective rate of MSI had no relation with the depth of invasion, which was 40.0%, 33 3%,39.3% and 34.5% at T1 to T4 stages(P<0.05),respectively, but it was significantly higher in cases with lymph node metastasis(51.4%) than those without metastasis(22.2%)(P<0.05).Although the detective rate of MSI showed an increasing trend in the mutated cases of p53 gene as compared with the no mutation cases,there was no relationship between MSI and p53 gene mutation (P<0.05).Conclusion These results suggest that the gene mutation of p53 and MSI may represent the different mechanisms of carcinogenesis.They can reflect the cytobiologic malignant behavior of gastric carcinoma in varying degrees, which may be of reference significance in analysing the prognosis of the patients in clinics.