Study of Diagnostic Oncogene Analysis of Gastric Carcinoma

目的：本研究的目的是确定胃癌中杂合性缺失（LOH）的准确频率，并明确一些临床病理因素与LOH的相关性。这可能为胃癌转移的研究提供一些重要的信息。材料和方法：从手术切除的标本中获得肿瘤和配对的正常粘膜组织。采用标准蛋白酶K酶切法和苯酚-氯仿萃取法提取基因组DNA。利用5个微卫星标记：D14S65、D14S68、D14S62、D14S267和D14S250，采用PCR -SSCP（单链构象多态性）方法对14q32的等位基因缺失进行检测。结果：在所有胃癌病例中，信息资料的平均检出率为42.7%。在5个检测的位点中，D14S65位点的LOH发生率最高（61%）。对于其他基因座，D14562、D14S267和D14S250的LOH识别率分别为61%、52%、41%和26%。胃癌淋巴结浸润及淋巴结转移程度与LOH的大小均有显著相关性。结论：我们首次报道了14q32等位基因缺失与胃癌淋巴扩散相关。这些发现不仅可能成为癌症淋巴扩散分子研究的立足点，而且可能导致胃癌晚期疾病的精确诊断。

OBJECTIVE : The purpose of this study was to determine the precise frequency of loss of heterozygosity (LOH) and to define the correlation between some clinicopathological factors and LOH in gastric carcinoma. It might lead to some important informations useful for study of metastasis of gastric carcinoma. MATERIALS AND METHODS : Tumor and paired normal mucosal tissues were obtained from surgically resected specimens. Genomic DNA was extracted according to the standard proteinase K digestion and phenol-chloroform extraction method. Allelic deletions on 14q32 were assessed with a PCR (polymerase Chain Reaction)-SSCP (single-strand conformation polymorphism) method using following five microsatellite markers : D14S65, D14S68, D14S62, D14S267, and D14S250. RESULTS : The average rate of informative data was 42.7% in all cases of gastric carcinomas analyzed. The highest incidence (61%) of LOH was observed at the D14S65 locus within the five loci examined. As for the other loci, LOH was recognized in 61% at Dl 4S68, 52% at D14562, 41% at D14S267, and 26% at D14S250. There was a significant correlation between the extent of LOH and both of lymphatic invasion and lymph node metastasis of gastric carcinoma. CONCLUSIONS We firstly reported that allelic deletion at 14q32 associated with lymphatic spread of gastric carcinoma. These findings might not only become a foothold for molecular studies on lymphatic spread of cancer and also lead to precise diagnosis of advanced disease in gastric cancer.