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目的：细胞遗传学和分子遗传学的分析证明，已发现的肿瘤抑制基因象Ｒｂ基因和ｐ５３基因的缺失或突变与膀胱癌的发生有关。最近，一种新的肿瘤抑制基因ｐ１６／ＣＤＫＮ２已被克隆定位于染色体９ｐ２１。在一些肿瘤标本及其部分肿瘤的培养细胞上，常检测到该基因的缺失。故研究该基因的改变与膀胱癌发生之间的关系，将有助于揭示膀胱癌的发生机制。方法：我们以磷酸钙沉淀技术将野生型ｐ１６／ＣＤＫＮ２ｃＤＮＡ转染到内源性ｐ１６／ＣＤＫＮ２序列有突变或缺失的膀胱癌细胞系ＲＴ４和ＲＴ１１２。对Ｇ４１８抗性选择所获阳性克隆，进行体外细胞生长及裸鼠致癌试验。结果：发现只有携带重组外源性ｐ１６／ＣＤＫＮ２ｃＤＮＡ的克隆才能生长传代，这些克隆的体外细胞生长试验及对裸鼠致癌性试验结果均与其亲代细胞类同，这和将野生型ｐ５３基因转染到该基因有改变的细胞中所获的结果相似。结论：提示ｐ１６／ＣＤＫＮ２基因的过量表达，可抑制膀胱癌细胞生长，该基因的失活可能与膀胱癌的发生有关，值得进一步研究。
OBJECTIVE: Cytogenetics and molecular genetics analysis demonstrate that the deletion or mutation of the tumor suppressor genes, such as Rb and p53, have been found to be associated with the development of bladder cancer. Recently, a new tumor suppressor gene, p16 / CDKN2, has been cloned to chromosome 9p21. In some tumor specimens and some of the tumor cells cultured, often detected in the absence of the gene. Therefore, to study the relationship between the changes of this gene and the occurrence of bladder cancer will help reveal the mechanism of bladder cancer. METHODS: Wild type p16 / CDKN2 cDNA was transfected into the bladder cancer cell lines RT4 and RT112 with mutations or deletions in the endogenous p16 / CDKN2 sequence by calcium phosphate precipitation. Positive clones were selected for resistance to G418 and in vitro cell growth and carcinogenesis in nude mice were tested. RESULTS: Only clones harboring recombinant exogenous p16 / CDKN2 cDNA were found to be passaged. The in vitro cell growth assays of these clones and their carcinogenicity in nude mice were similar to their parental counterparts, and the wild-type p53 gene was transfected into The results obtained in cells with altered genes were similar. Conclusion: The overexpression of p16 / CDKN2 gene can inhibit the growth of bladder cancer cells. The inactivation of this gene may be related to the occurrence of bladder cancer, which deserves further study.