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

我们采用18个不同的多态性位点，通过聚合酶链反应（PCR）-杂合性缺失（洛）分析，研究了54例无亲缘关系的口腔鳞癌患者的肿瘤。这些结果使一个推定的最小区域的删除映射在13 q 14.3的识别。通常缺失的区域位于RBI基因座附近，但位于端粒。我们还检查了相同的样品的RBI基因的失活和突变的免疫组化分析，PCR-单链构象多态性（SSCP）分析，以检测RBI基因的任何突变。然而，在我们的样本中既没有检测到RBI基因的突变也没有检测到RBI基因的失活。有趣的是，我们发现13 q14.3的洛缺失与淋巴结转移显著相关。结果提示D13 S273-D13 S176位点附近存在一个新的抑癌基因，该基因可能与口腔鳞癌的淋巴结转移有关。使用在这些位点有和没有洛合性缺失的肿瘤。分离出两个DNA片段，并确认存在于染色体13 q上。以这些DNA片段为探针，北方印迹分析显示，这些片段在有淋巴结转移和无淋巴结转移的肿瘤中表达水平不同，提示这些片段可能是参与转移的抑癌基因的一部分。

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.