食管鳞癌及其前驱病变基因杂合子缺失的研究

Loss of heterozygosity in esophageal squamous cell carcinoma and its precursor lesion

目的 通过对食管黏膜高级别上皮内瘤变和鳞状细胞癌中的等位基因杂合子缺失(LOH)的检测,以期发现与食管鳞状细胞癌关系密切的抑癌基因。方法 应用显微切割,PCR扩增、凝胶电泳、放射自显影等技术,对照分析正常体细胞、食管鳞状上皮高级别上皮内瘤变和食管鳞状细胞癌组织中LOH的变化,并就各位点杂合子缺失率与患者的临床病理参数分别进行单因素分析。结果 高级别上皮内瘤变中7个位点的LOH依次为D13S802(40%)、D9S171(33%)、D13S267(320%)、D13S221(31%)、D9S942(30%)和D17S520(240%),而D17S1798在本组上皮高级别上皮内瘤变中未发现杂合子缺失。在食管鳞状细胞癌组织中,上述7个位点的LOH率依次为D13S267(71%),D13S802(58%),D17S520(55%)、D13S221(45%)、D9S942(43%)、D9S171(33%)和D17S1798(11%)。应用SPSS软件对7个微卫星序列的等位基因LOH率与患者的病理学分级、临床病理分期及是否有淋巴结转移进行单因素分析,差异均无显著性(P>0.05)。结论 (1)从正常黏膜到上皮内瘤变再到食管鳞癌的发生过程中,同时伴随基因异常的逐步积累。(2)13q12.12上的D13S802附近可能存在着主要与食管鳞状细胞癌早期发生有关的抑癌基因。(3)13q12.3上的D13S267附近、17p13.1上的D17S520和17p13.

Objective To detect the loss of heterozygosity (LOH) in esophageal squamous cell carcinoma and adjacent high-grade squamous dysplasia, and to evaluate possible tumor suppressor genes in the development and progression of invasive malignancy. Methods LOH was detected in normal esophageal mucosa, high grade squamous dysplasia and esophageal squamous cell carcinoma using microdissection and polymerase chain reaction technology. The changes of LOH at seven microsatellite markers and the relationship between LOH rate and clinicopathologic parameters were analysized. Results In high grade squamous dysplasia, LOH was detected at D13S802 (40%), D13S267 (32%), D13S221 (31%), D9S942 (30% ) , D17S520 (24% ) and D9S171 (33% ). However, D17S1798 LOH was not detected. In invasive squamous cell carcinoma, LOH was detected as follows; D13S267 (71% ), D13S802 (58% ) , D17S520 (55%), D13S221 (45%), D9S942 (43%), D9S171 (33%) and D17S1798 (11%). The frequency of LOH in the seven microsatellite markers, the pathologic grade, clinical stage and occurrence of lymph node metastasis did not show any statistically significant correlation (P > 0. 05). Conclusions The progression from normal squamous epithelium to high grade squamous dysplasia and subsequently to invasive squamous cell carcinoma of the esophagus was associated with accumulation of genetic errors. Possible tumor suppressor genes related to the development of esophageal squamous cell carcinoma may exist near D13S802 (13ql2. 12). Possible tumor suppressor genes near D13S267 (13ql3. 1) , D17S1798 (17pl3. 3 ) and D17S520 (17pl3. 1) may be related to the progression of esophageal squamous cell carcinoma.