食管癌9号染色体多位点等位基因的杂合性缺失

目的 探讨食管鳞状细胞癌(ESCC)发生、发展过程中基因的变化及多位点之间的相关性,发现9号染色体上与ESCC密切相关的抑癌基因.方法 通过手工显微切割、PCR扩增、变性聚丙烯酰胺凝胶电泳、AgNO3染色等技术,对照正常组织,检测不典型增生及癌组织在9号染色体上6个微卫星位点的杂合性缺失(LOH)的情况,同时分析该6个位点之间的相关性.结果 在有信息的病例中,正常组织未发生LOH,不典型增生总LOH率为17.2%(25/145),ESCC总LOH率为24.9%(43/173);不典型增生和ESCC组织中,6个微卫星位点的LOH率依次分别为D9S162(20.8%、36.7%)、D9S171(33.3%、36%)、D9S753(34.8%、46.2%)、D9S1748(4.2%、13.8%)、D9S242(14.3%、21.2%)、D9S43(0、0).无论在不典型增生还是在癌组织中,其LOH在9号染色体的各位点之间差异有统计学意义(x2=17.26,P<0.005;X3=22.66,P<0.005).结论 从正常组织到不典型增生再到癌变的过程中,存在染色体改变的累积.D9S171、D9S162、D9S242、D9S753位点存在较高的等位基因LOH,均>20%,各位点或其附近可能存在与ESCC发展相关的抑癌基因.

Loss of multi-sites allde heterozygosity on chromosome 9 in esophageal carcinoma

Objective To investigate the gene variation and the dependability and to evaluate the possible tumor suppressor genes on chromosome 9 in the development and progression of EC. Methods LOH was detected in normal esophageal mucosa, high-grade squamous dysplasia and esophageal squamous cell carcinoma by microdissection, polymerase chain reaction, denaturing polyacrylamide gel eleetrophoresis and silver nitrate staining technology. The changes of LOH at six microsatellite markers and the relationship between LOH rate were analyzed. Results In the informative cases, total frequency of LOH was 17.2 % in high-grade squamous dysplasia and 24.9 % in esophageal squamous cell carcinoma. In high grade squamous dysplasia and squamous cell carcinoma, LOH was detected at marker D9S162 (20.8 %, 36.7 %), D9S171 (33.3 %, 36 %), D9S753(34.8 %, 46.2 %), D9S1748(4.2 %, 13.8 %), D9S242(14.3 %, 21.2 %), D9S43(0, 0). The frequency of LOH showed significant difference among the six microsatellite markers (X2=17.26, P< 0.005; X2=22.66,P<0.005). Conclusion The progression from normal squamous epithelium to high-grade Squamous dysplasia and subsequently to squamous cell carcinoma of the esophagus is associated with accumulation of chromosomal change. The situs of D9S171, D9S162, D9S242, D9S753 exist higher LOH and all exceed 20 %. Possible tumor suppressor genes at or near D9S171, D9S162, D9S242, D9S753 may be related to the progression of esophageal squamous cell carcinoma.