食管鳞癌组织的常见基因组DNA异常改变及其临床预后的相关性分析

目的：分析食管鳞癌组织的常见基因组DNA改变，以期获得可能用于该病诊断和预后判断的分子标志。方法：对112例食管鳞癌手术组织标本，提取基因组DNA采用聚合酶链式反应（PCR）和变性聚丙烯酰胺凝胶电泳（PAGE）检测位于染色体3p和13q上的6个微卫星的杂合性丢失（LOH）情况，并与我们已报道的高频基因突变进行联合分析。结果：在被测的微卫星中，D3S1768的LOH频率最高，为48.9%；D3S2452的LOH最低，为28.8%。当与所测突变联合分析时，发现一个较优的组合，包括D3S1768、D13S171、D13S1493、TP53和TTN，该组合中任意2个标志同时出现异常改变的频率为75.6%，远高于任何单一标志的改变频率。生存分析的结果显示，在本组病例中所测微卫星LOH频率与患者生存率之间无统计学相关性，但PBRM1和SYNE2基因突变多存在于生存期较短的病例中。当将基因突变与淋巴结转移联合分析时，发现这两类指标同为阳性患者的总生存期显著短于仅有其一阳性或均为阴性的患者（P=0.027）。结论：食管鳞癌组织中存在较高频率的微卫星D3S1768杂合性丢失，包括TP53突变的标志物组合有助于提高检测食管鳞癌的敏感度，PBRM1、SYNE2基因突变联合淋巴结转移可作为食管鳞癌预后判断的指标。

Identification of predominant genome DNA alterations and their clinical implication in esophageal squamous cell carcinoma

OBJECTIVE: This study aimed at identifying common genomic DNA alterations in esophageal squamous cell carcinoma (ESCC) which can be used as molecular markers for the detection and prognostic determination of the disease. METHODS: Genomic DNAs were extracted from tumors and morphologically normal operative margins of 112 ESCCs. Polymerase chain reactions (PCR) and polyacrylamide gel electrophoresis (PAGE) were performed to detect alterations of six microsatellite sites on chromosomes 3p and 13q. Loss of heterozygosity (LOH) of the microsatellites was further analyzed in combination with the frequently mutated genes that had been reported in our previous study. RESULTS: Among the detected microsatellite sites,D3S1768 had the highest LOH frequency (48.9%),while D3S2452 had the lowest (28.8%). When conjointly analyzed with the frequent mutations,we discovered an optimal five-marker combination including LOH of D3S1768,D13S171,D13S1493,and mutations of TP53 and TTN. Alteration of any two markers arising together in this combination had a frequency of 75.6% which was much higher than that of any single marker. The results of survival analysis showed that there was no statistical correlation between LOH of the microsatellites in this group of ESCC and survival of the patients. However,the mutations of PBRM1 and SYNE2 mainly presented in the case of short-survival. When mutations of these two genes were combined with lymph node metastasis,the overall survival time of ESCC patients with at least two positive indicators was significantly shorter than those with only one positive index or negative ones (P=0.027). CONCLUSION: A high LOH frequency was detected with microsatellite D3S1768 in ESCC. A five-marker combination,including TP53,increased the sensitivity of detecting ESCC. PBRM1 and SYNE2 mutations combined with lymph node metastasis might become an index of ESCC prognosis.