p16，p15基因在多种原发恶性肿瘤与肿瘤细胞株中存在状态的研究

THE STATUS OF p16 AND p15 IN PRIMARY TUMORS AND CELL LINES

由于多种肿瘤细胞株存在ｐ１６、ｐ１５基因的缺失与点突变，而ｐ１６、ｐ１５蛋白本身又能抑制ＣＤＫ４、ＣＤＫ６的活性，阻止细胞增生，为了确定ｐ１６、ｐ１５基因在原发恶性肿瘤发生、发展过程中的作用，应用多重ＰＣＲ、ＳＳＣＰ分析及直接ＤＮＡ序列测定技术检测分析了３５７例原发肿瘤、２９个肿瘤细胞株、９１例散发的多发性肿瘤患者及具有家族性肿瘤高发倾向的肿瘤患者的外周血标本，６１例健康成人外周血标本作为对照。结果表明：原发恶性肿瘤组织中ｐ１６、ｐ１５基因缺失的频率明显低于肿瘤细胞株；ｐ１６、ｐ１５基因缺失的检出率随肿瘤的组织学类型而异；基因缺失的范围较大，通常累及ｐ１６和ｐ１５两个基因；ｐ１６基因编码区的点突变在本组肿瘤中罕见；某些肿瘤如膀胱癌、肾癌尽管存在９ｐ２１－ｐ２２的ＬＯＨ，但却未检出有ｐ１６及ｐ１５基因缺失或点突变。为肿瘤的病因学研究提供了资料。

Aberrations of chromosome 9p 21-22 are involved in the genesis of many forms of cancer.Recently,the gene p16 and p15 have been assigned to this region.p16 and p15 are the inhibitors of Cyclin-cdk4 and Cyclin-cdk6 complex and have been implicated in a wide variety of cancer types.This study investigated and compared the status of p16 and p15 in primary tumors and cell lines.Multiple PCR of p16,p15 and control gene,PCR amplification of microsatellite DNA markers,and volume analysis of PCR preducts were used for determining of gross deletions:SSCP analysis and DNA sequencing were used for defining of subtle mutations.A total of 5 homazygous deletions,4 hemizygous deletions were found in 29 tumor cell lines and 8 homozygous deletions and 37 hemizygous deletions in 357 primary tumors,and a total of 10 different types of variants were observed in coding sequence of p16 exon 2 and adjacent intron sequence,The results suggested:(1)Homozygous deletions of p16 or p15 were comparatively rare and far less common than previously reported;(2)The incidence of p16 and p 15 deletions varied significantly among different tumor types;(3)Most deletions involved both p16 and p15 genes;(4)Sequence variations in the coding sequence of p16 were comparatively rare among the tumor types detected.