SPECIFIC GENETIC ANALYSIS OF PREMALIGNANT LESIONS OF THE PROSTATE USING SELECTIVE ULTRAVIOLET RADIATION FRACTIONATION TECHNIQUE

目的：应用选择性紫外辐射分离技术检测苏木精伊红切片上组成PIN和腺癌的特定细胞p53抑癌基因的突变。材料与方法：回顾80例根治性前列腺切除术和20例尸检的HE切片，采用SURF法（Shibata, 1993）提取PIN、腺癌和高度前列腺增生的特异性DNA，采用聚合酶链反应扩增p53基因外显子4 ~ 9，单链构象多态性和直接测序检测突变。免疫组化法检测Ki-67、p53、bcl-2、p21(WAF!)， TuUNEL法检测细胞凋亡。用CAS200计算机图像分析系统对结果进行定量评价。结果：前列腺基底细胞中检测到野生p53的表达，免疫阳性细胞数量随PIN分级的增加而减少。20%的腺癌中检测到P53核积累，12.5%的腺癌中检测到LOH。10%的PIN检出LOH。2例腺癌外显子4突变，6例外显子5突变，2例外显子7突变。低度PIN未见突变。10%的高级别PIN显示突变，所有这些突变都与腺癌同时发生，并且显示突变点与相关癌症的完美一致性。讨论：p53突变发生在小部分高级别PIN伴发腺癌患者中。然而，在无腺癌的PIN中未发现突变。考虑到这些因素，PIN中p53基因的改变可能是随后的事件，而不是前列腺癌发生的先决条件。

Objectives : To examine mutations of p53 tumor suppressor gene of specific cells constituting PIN and adenocarcinoma on hematoxylin eosin sections by selective ultraviolet radiation fractionation technique.Materials and Methods : Reviewing HE sections from 80 radical prostatectomies and 20 autopsies, DNA specific for PIN,adenocarcinoma and benigh prostatic hyperplasia was extracted by SURF method (Shibata, 1993) and exons 4 to 9 of p53 gene were amplified by polymerase chain reaction and mutations were examined by single strand conformation polymorphism and direct sequencing. Ki-67, p53, bcl-2 and p21(WAF! ) were detected by immunohistochemistry and apoptosis was detected by TuUNEL method. The results were quantitatively assessed by CAS200 computer image nalysis system.Results : Expression of wild p53 was detected in prostatic basal cells and the number of immunopositive cells decreased with advancing grade of PIN.P53 nuclear accumulation was detected in 20% of adenocarcinomas and LOH was detected in 12.5% of those. LOH was detected in 10% of PIN.Mutations of exon 4 in 2 adenocarcinomas, exon 5 in 6 and exon 7 in 2. There were no mutations found in low grade PIN.Ten percent of high grade PIN showed mutations all of which were concurrent with adenocarcinomas and showed a perfect concordance of mutation point with associated cancer.Discussion : Mutations of p53 occurrs in a small subset of high grade PIN accompanying adenocarcinoma. However, there was no mutation found in PIN without adenocacinoma. Taking these into consideration, p53 gene alteration in PIN may be asubsequent event rather than a antecedant to prostatic carcinogenesis.