25例原发性肝细胞性肝癌中P16基因失活的研究

目的 调查Ｐ１６基因是否与原发性肝细胞性肝癌（ＰＨＣＣ）的发生有关。方法 采用多重ＰＣＲ分析法、单链构象多态性（Ｓｉｎｇｌｅ ｓｔｒａｎｄ ｃｏｎｆｏｒｍａｔｉｏｎ ｐｏｌｙｍｏｒｐｈｉｓｍ，ＳＳＣＰ）分析法及以ＰＣＲ为基础的甲基化分析法对２５例原发性细胞性肝癌（ＰＨＣＣ）标本及其相应的非肿瘤肝细胞标本中Ｐ１６基因的缺失、点突变及甲基化情况进行检测。用免疫组织化学法对３５例（包括前述已作基因检测的

Study of inactivation of P16 gene in 25 cases of primary hepatocellular carcinoma

Objective: To determine whether P16 is involved in the genesis of hepatocellular carcinoma (PHCC). Methods: Specimens of PHCC and noncarcinomatous liver tissues were collected from 25 cases of PHCC. The deletion of P16 gene exon 1 and exon 2 was identified with comparative multiplex PCR, the point mutation of P16 gene exon 2 was examined with single strand conformational polymorphism (SSCP) and the status of P16 gene methylation was screened with PCR based methylation analysis. In addition, 35 specimens of paraffin embedded PHCC tissue including the surrounding noncarcinomatous liver tissues were examined for P16 protein expression with immunohistochemical analysis. Results: 2 homozygous deletions and 1 hemizygous deletion were found in the 25 PHCC specimens. In the remaining 22 specimens, no point mutation was found. Hypermethylation occurred in 24% (6/25) of the cases and the surrounding noncarcinomatous were always unmethylated at the P16 locus. Loss of P16 protein expression occurred in 45.7% (16/25) of the cases and all the noncarcinomatous liver tissues were P16 staining positive. In the 25 cases of PHCC examined for P16 gene, 3 cases showed P16 gene deletion and 6 cases were found to have methylation of P16 gene. And all the 25 cases were absent for P16 protein expression. Conclusion: Inactivation of P16 gene may play and important role in the genesis of primary PHCC.