Isolation of a novel tumor suppressor gene on the chromosome 13q14 associated with metastasis of oral cancer

我们用聚合酶链式反应-杂合性缺失(LOH)分析方法，使用18个不同的多态基因座，对54例无关口腔鳞癌患者的肿瘤进行了研究。结果使定位于13q14.3的推测的最小缺失区域得以确定。通常缺失的区域位于RBI基因座附近，但端粒。我们还通过免疫组织化学分析、PCR-单链构象多态(SSCP)分析检测相同样本的RBI基因失活和突变，以检测RBI基因的任何突变。然而，在我们的样本中没有检测到RBI基因的突变或失活。有趣的是，我们发现13q14.3的杂合性缺失与淋巴结转移显著相关。这些结果提示在D13S273-D13S176基因座附近存在一个新的抑癌基因，该基因可能在口腔鳞癌的淋巴转移中起作用。目的：寻找D13S273-D13S176基因座附近可能发挥作用的候选抑癌基因，并利用这些基因座上有无杂合性缺失的肿瘤进行差异显示和代表性差异分析。分离到两个DNA片段，证实存在于染色体13q上。以这些DNA片段为探针，Northern印迹分析显示，这些片段在有和无淋巴结转移的肿瘤中的表达水平存在差异，提示这些片段可能是参与转移的肿瘤抑制基因的一部分。

We studied tumors from 54 unrelated patients with oral SCC by the polymerase chain reaction (PCR) -loss of heterozygosity (LOH) assay, using 18 different polymorphic loci. The results enabled the identification of a putative minimal region of deletion mapped at 13q 14.3. The commonly deleted region is located close, but telomeric to the RBI locus. We also examined the same samples for inactivation and mutation of the RBI gene by immunohistochemical analysis, PCR-single-strand conformational polymorphism (SSCP) analysis to detect any mutation of the RBI gene. However, neither mutation nor inactivation of the RBI gene was detected in our samples. Interestingly, we found significant correlation between LOH of 13q14.3 and lymph node metastasis. These results suggest the existence of a new suppressor gene near D13S273-D13S176 loci, which may play a role in lymph node metastasis of oral SCC.To identify a candidate gene for the putative tumor suppressor gene near D13S273-D13S176 loci, which may play a role in lymph node metastasis, differential display method and representational difference analysis, using tumors with and without LOH at these loci. Two DNA fragments were isolated and confirmed the presence on chromosome 13q. Using these DNA fragments as probes, Northern blot analysis revealed the different expression levels between tumors with and without lymph node metastasis, suggesting that these fragments may be a part of putative tumor suppressor genes involved in metastasis.