卵巢癌患者血清DNA BRCA1/TP53基因杂合性丢失的研究

Loss of heterozygosity at BRCA1/TP53 in serum DNA from ovarian cancer patients

目的 通过对卵巢癌患者血清DNA及其相应肿瘤组织DNA的BRCA1/TP5 3等位基因杂合性丢失 (LossofHeterozy gosity ,LOH)的研究 ,探讨上述基因变异与卵巢癌发生发展之间的相关性。方法 采用PCR并结合二核苷酸 (CA)n重复序列多态性的方法 ,分别对 76例卵巢癌 (其中 17例伴有匹配新鲜手术标本 )及 10例卵巢良性肿瘤患者的血清DNA中 4个微卫星标志BRCA1(D17S5 79、D17S85 5 )和TP5 3(TP5 3、D17S786 )进行LOH检测。结果 17对卵巢癌血清DNA与相应肿瘤组织DNA中BRCA1/TP5 3LOH发生频率之间存在明显的相关性 (P <0 .0 5 )。在 76例血清DNA标本中 5 9例 (77.6 % )至少存在一个位点LOH ,以及 4 3例 (5 6 .6 % )可出现两个以上位点LOH ,而 10例良性肿瘤患者血清DNA均未发现LOH。卵巢癌患者血清DNA中上述基因杂合性丢失频率以及所累及的微卫星位点的数目与FIGO分期呈正相关。结论 本文结果提示卵巢癌患者血清DNA与肿瘤组织DNA中BRCA1及TP5 3基因LOH密切相关 ,从而证实了卵巢癌患者血清DNA主要来源于原发肿瘤组织。鉴于血清BRCA1/TP5 3LOH与卵巢癌恶性程度相关 ,故检测卵巢癌患者血清DNABRCA1/TP5 3等位基因LOH有望作为一种反映癌症患者分期及预后的分子标记。

Objective Aim of the study is to investigate the frequency of LOH (Loss of Heterozygosity) at BRCA1/TP53 in the serum DNA from ovarian cancer and its clinical application. Methods 76 ovarian cancer serum DNA samples with 17 corresponding tumor tissues and 10 benign ovarian tumors were obtained, and DNA samples extracted from serum and tissues were examined for LOH by using of PCR with four polymorphic microsatellite markers: BRCA1(D17S579、D17S855) and TP53(TP53、D17S786). Results Matched serum and tissue DNAs from 17 ovarian cancer patients showed significant concordance of LOH (P<0.05). LOH in at least one of four loci occurred in 59 out of 76 (77.6%) serum samples, while 43 serum samples (56.6%) exhibited LOH at more than one locus. According to FIGO staging, there was a trend that the rate of LOH was higher in more advanced stages. No LOH was found in 10 benign ovarian tumors. It was also found that the frequency and the number of microsatellite markers with LOH was increased with tumor progressed. Conclusion (1) Circulating DNA in serum of ovarian cancers mainly derived from primary tumor tissue. (2) Since the strong correlation of BRCA1/TP53 LOH between serum and tissue samples and the higher frequency of LOH with the development of ovarian cancer, the detection of LOH in serum DNA may be used as a molecular marker for staging and monitoring of human ovarian cancer.