Fracchiolla N S, Capaccio P, Carboni N, Pagliari A V, Neri A, Ronchett D, Pruner G, Silvotti M G, Pignataro L, Buffa R, Broich G
Laboratorio de Ematologia Sperimentale e Genetica Molecolare, Servizio di Ematologia, Istituto di Scienze Mediche, Milan, Italy.
Anticancer Res. 1999 Mar-Apr;19(2A):1043-51.
We investigated the role of apoptosis and its potential alterations in laryngeal squamous cell carcinomas (LSCCs) by evaluating bax, bcl-2 and p53 protein expression in 50 cases and by characterising the molecular status of the bax and p53 genes.
p53 and bax gene mutations were investigated by means of PCR/SSCP and direct DNA sequencing, and bax, bcl-2 and p53 protein expression by means of immunohistochemistry.
We identified p53 gene mutations in 17/50 cases (34%); p53 expression in 26 of the 50 cases (52%); bcl-2 expression in 5/50 cases (10%); bax expression in 32/47 cases (68%). 18/33 cases with a wild type p53 gene overexpressed p53 protein: 12 cases (approximately 66%) were bax+/bcl-2-. Of the remaining cases without p53 protein expression, seven cases (approximately 47%) were bax+/bcl-2-.
Our observations suggest that the overexpression of p53 may contribute to the repression of bcl-2 and the induction of bax expression in LSCCs. However, the fact that a number of cases not expressing p53 did not present any clear up-regulation of bax or down-regulation of bcl-2 suggests that bcl-2 and bax may be regulated by various mechanisms other than p53.
我们通过评估50例喉鳞状细胞癌（LSCC）中bax、bcl - 2和p53蛋白的表达，并对bax和p53基因的分子状态进行特征分析，研究了细胞凋亡及其潜在改变在喉鳞状细胞癌中的作用。
通过PCR/SSCP和直接DNA测序研究p53和bax基因突变，通过免疫组织化学研究bax、bcl - 2和p53蛋白表达。
我们在17/50例（34%）中鉴定出p53基因突变；50例中有26例（52%）表达p53；5/50例（10%）表达bcl - 2；32/47例（68%）表达bax。18/33例野生型p53基因的病例中p53蛋白过表达：12例（约66%）为bax+/bcl - 2-。在其余无p53蛋白表达的病例中，7例（约47%）为bax+/bcl - 2-。
我们的观察结果表明，p53的过表达可能有助于抑制喉鳞状细胞癌中bcl - 2的表达并诱导bax的表达。然而，一些不表达p53的病例未出现bax明显上调或bcl - 2明显下调的事实表明，bcl - 2和bax可能受p53以外的多种机制调控。
