Detection of Serum Aberrant CDKN2/P16 DNA in Colorectal Cancer

Objective： To search for a biomarker for colorectal cancer. Methods： The MSP, SSCP and deletion tests with serum have been taken simultaneously in 100 cases of colorectal cancer and 2 groups of controls, as well as the specimens of 26 cancer tissues and 22 paracancerous tissues and 29 cases of benign disease tissues for a contrast. Results： The aberrant methylation rate of P16 in the serum was 69.00%, deletion rate 4.00% and suspicious point mutation rate 15.00% in colorectal cancer patients. The data of cancer tissues were the same as those of the serum, but in paracancerous tissue those were significantly lower. In 10 cases, sequencing analysis revealed that there were 3 cases of missense, one case of frameshift and one case of nonsense. Among them, four cases had P16 protein deletion. As a tumor marker, the sensitivity of combined use of three methods was 88.00%, specificity 96.87% and accuracy 90.15%. The combined use of MSP and SSCP could obtain the same results. Conclusion： The content of DNA in serum is minimal, but it reflects the tumor burden of patients. The 10^-3 fragments of DNA could be detected in the serum by MSP. It can be used in the clinical diagnosis or popular investigation, and long-term postoperative follow-up.

甲状腺癌组织端粒酶激活与p16基因失活的关系

目的探讨甲状腺癌细胞增殖、分化与端粒酶激活及抑癌基因p16失活(缺失突变)之间可能存在的关系。方法应用TRAP、多重PCR、免疫组化法检测42例甲状腺癌与16例癌旁组织端粒酶活性、P16基因外显子2缺失、P16蛋白表达。结果甲状腺癌组端粒酶活性90.48%,高于癌旁组织(P<0.01);甲状腺癌p16基因外显子2纯合缺失率28.57%,相应癌旁组未检出(P<0.01);甲状腺癌P16蛋白表达缺失率40.48%,高于癌旁组(P<0.05);甲状腺癌P16蛋白表达缺失率高于p16基因外显子2缺失率。结论端粒酶激活与p16基因失活以及P16蛋白表达下调可能是甲状腺癌变过程中的重要分子事件,甲状腺癌中p16基因失活可能是端粒酶激活的一种途径。

端粒酶活性在乳腺良恶性肿瘤中的表达以及与P_(16)、C-erbβ-2的相关性研究

目的 :探讨乳房恶性肿瘤组织中端粒酶的表达 ,端粒酶与肿瘤病理行为学的关系以及与其他癌基因和抑癌基因的关系。方法 :应用端粒重复扩增方法对 6 0例乳房良恶性肿瘤组织、配对癌旁组织及非癌组织进行端粒酶活性测定 ,并同时进行 P1 6缺失分析及 C-erbβ-2蛋白表达的检测 ,结合临床病理指标进行分析。结果 :乳腺癌中端粒酶活性表达阳性率达 80 %。在乳癌中 P1 6基因缺失、C-erbβ-2蛋白阳性表达同时 ,端粒酶活性检测分别达 92 .3 %和 91.3 %。结论 :说明端粒酶活性和肿瘤的关系密切 。