Oyasu R, Nan L, Szumel R C, Kawamata H, Hirohashi S
Department of Pathology, Northwestern University Medical School, Chicago, Illinois, USA.
Mod Pathol. 1995 Feb;8(2):170-6.
We examined 60 cases of human urothelial carcinomas (27 superficial and 33 deeply invasive) for the frequency of p53 gene mutations. Forty-two cases were analyzed by both the immunohistochemical and the single-strand conformation polymorphism (SSCP) methods, and the remaining 18 cases were assayed by SSCP alone. For the latter assay, exons 4 to 8 were amplified by polymerase chain reaction, and the amplified nucleotides were analyzed for the evidence of mutations by gel electrophoresis. When mobility shift was observed, direct nucleotide sequencing was performed to determine mutation sequence. Three superficial and eight deeply invasive carcinomas demonstrated evidence of mutations. Mutations involved various codons randomly. The fact that all tumors with mutations of the p53 gene except for one were of high nuclear grade (grade III) suggests that p53 mutation is associated with the progression of bladder cancers. Our results indicate that SSCP is a sensitive screening assay for detecting gene mutations. Immunohistochemical analysis is also a sensitive method but may yield false positive as well as false negative results.
我们检测了60例人膀胱尿路上皮癌（27例表浅性和33例浸润性）中p53基因突变的频率。42例通过免疫组化和单链构象多态性（SSCP）方法进行分析，其余18例仅通过SSCP检测。对于后一种检测，通过聚合酶链反应扩增外显子4至8，并通过凝胶电泳分析扩增的核苷酸以寻找突变证据。当观察到迁移率改变时，进行直接核苷酸测序以确定突变序列。3例表浅性癌和8例浸润性癌显示有突变证据。突变随机涉及各种密码子。除1例之外，所有p53基因突变的肿瘤均为高核分级（III级），这一事实表明p53突变与膀胱癌的进展相关。我们的结果表明，SSCP是一种检测基因突变的灵敏筛查方法。免疫组化分析也是一种灵敏方法，但可能产生假阳性和假阴性结果。
