微切割喉鳞状细胞癌9p13-23区域微卫星杂合性缺失的研究

Loss of heterozygosity on chromosome 9p13-23 in microdissected laryngeal squamous cell carcinoma by microsatellite analysis

目的 探讨喉鳞状细胞癌 (简称鳞癌 )在 9p13 2 3区域微卫星 (microsatellite)发生杂合性缺失 (lossofheterozygosity,LOH)的热点。方法 采用显微切割法从病理切片中挑取肿瘤组织 ,选取位于 9p13 2 3区域的 13个高多态性微卫星引物对 42例喉鳞癌组织进行聚合酶链反应和变性凝胶电泳。结果 ① 42例喉鳞癌在 9p13 2 3区域等位基因LOH的总发生率是 97 6 %(4 1/ 42 )。在 13个微卫星引物中 ,LOH发生率最高者是位于 9p2 2 2 3的D9S16 2 (89 5 %) ,其次是位于 9p2 1的D9S171(80 0 %)。与p16基因紧密连锁的D9S1748的LOH发生率仅 5 0 0 %。②等位基因缺失作图分析发现 42例喉鳞癌组织在 9p13 2 3上存在 2个明显的LOH较小区域 ,分别位于 9p2 1的D9S16 1～D9S171之间和 9p2 2 2 3的IFNA和D9S16 2之间。结论 喉鳞癌在 9p13 2 3区域除抑癌基因p16以外可能还存在 2个或 2个以上候选抑癌基因 ,这些候选抑癌基因也许和p16一样与喉鳞癌的发生、发展密切相关。

Objective Loss of heterozygosity (LOH) studies indicate that allelic loss associated with the development of head and neck of squamous cell carcinoma occurs most frequently at 9p21-22. However, the target of chromosome 9p21-22 loss has been the source of significant debate. A putative tumor suppressor gene, p16, has been identified at the 9p21 location, but genetic alterations of p16 located in this region are unusual. To refine the hot spots of LOH on chromosome 9p13-23 will be helpful to find other putative tumor suppressor genes in laryngeal squamous cell carcinoma. Methods The sections of paraffin-embedded tumor tissues were microdissected to enrich for neoplastic cells. LOH on 9p13-23 was analyzed in a set of 42 paired blood and tumor samples using polymerase chain reaction(PCR) with 13 highly polymorphic microsatellite markers. Results Of the 42 total tumors, 41(97.6%) showed LOH in at least one of the microsatellite markers tested at the chromosome 9p13-23 region. The most frequently deleted marker was D9S162 with in 17 of 19 (89.5%) informative samples. The marker D9S171, which is located in 9p21, had LOH detected in 12 of 15 informative cases (80.0%). LOH at the D9S1748 marker (closest to the p16 gene locus) was detected in 18 of 36 informative cases (50.0%). Fine deletion mapping also revealed two minimal regions of LOH encompassing markers D9S161-D9S171 at 9p21 and IFNA-D9S162 at 9p22-23. Conclusion These findings imply the high frequency of LOH at 9p13-23 in laryngeal squamous cell carcinoma and the presence of at least two as yet unidentified tumor suppressor genes in 9p13-23 region. Those putative tumor suppressor genes may become inactivated during the progression of the laryngeal squamous cell carcinoma.