食管鳞状细胞癌p53基因杂合性缺失和基因突变的相关研究

Loss of hetrozygosity of p53 gene and p53 gene mutation in esophageal squamous cell carcinoma

目的检测食管鳞状细胞癌(ESCC)中p53基因杂合性缺失(LOH),p53基因突变及蛋白表达的情况,分析其与临床病理和预后的相关性。方法采用聚合酶链反应—单链构象多态性分析(PCR-SSCP)和免疫组织化学方法(SP)检测56例ESCC中p53基因LOH和p53基因蛋白的表达情况。结果56例ESCC组织中p53蛋白阳性表达率为60.7%(34/56),它与患者的年龄、性别和家族史无关(P>0.05),有或无淋巴结转移的阳性率分别为81.0%(17/21),48.6%(17/35);生存率低于3年组和高于3年组的p53阳性表达率为73.9%(17/23),46.4%(13/28),差异有统计学意义(P<0.05)。p53基因LOH率为80.5%(33/41),与患者的年龄、性别、家族史和有无淋巴结转移无关,与3年生存率有相关性(P<0.05)。p53基因总突变率为76.8%(43/56),突变位于17号染色体第4外显子者5例,第5外显子者23例,第6外显子者1例,第7外显子者4例,第8外显子者7例,有3例在内含子。p53基因突变/过度表达率为46.4%(26/56),两种方法检测的符合率为55.4%(31/56)。结论p53基因在ESCC的发生、发展中可能发挥重要作用,伴有p53基因LOH/p53蛋白过度表达的3年生存率明显降低。p53蛋白阳性表达的ESCC更易发生淋巴结转移,可作为判断食管癌预后的参考指标之一。

Objective To investigate loss of heterozygosity（LOH） of p53 gene, p53 gene mutation and protein accumulations in esophageal squamous cell carcinoma（ESCC） and correlation with clinicopathological feature and prognosis. Methods PCR-SSCP and Immunohistochemistry techniques were used to detect for LOH of p53 gene, p53 gene mutation and protein accumulation in 56 ESCC. Results The general positive rate of p53 protein expression was 60.7 %（34/56）. Its expression had no statistical significance with Age, Sex and Family history （P 〉0.05）. The positive rate was 81.0 %（17/21） in those with lymph node metastasis vs 48.6 % （17/35） in those without lymph node metastasis. The 3 year survival rate with p53 protein expression was significantly lower than those without p53 protein expression. [46.4 %（13/28） and 73.9 %（17/23） respectively]. The LOH rate of p53 gene in ESCC was 80.5 %（33/41）, which had no obvious correlation with Age, Sex, Family history and lymph node metastasis, but had obvious correlation with the 3 year survival rate（P 〈 0.05）. p53 gene mutation was detected in 77 %（43/56） of the same speciments by PCR-SSCP. In 5 cases, the mutations were located on Exon 4, 23 were on Exon 5, 1 on Exon 6, 4 on Exon 7,7 on Exon 8, 3 on Intron respectively. The rate of p53 gene mutation/overexpression was 46.4 % （26/56）. The concordance rate of immunohistochemistry and PCR-SSCP was 55.4 %（31/56）. Conclusion p53 gene may play an important role in the pathogenesis of esophageal squamous cell carcinoma, p53 gene LOH/p53 overexpression ever reduced the 3 year survival rate in ESCC. p53 protein expression was associated with increased lymph node metastasis and can be considered as a predicting marker of prognosis.