儿童急性白血病p16基因纯合子缺失和点突变的实验研究

为探讨p1 6基因纯合子缺失和点突变与儿童急性白血病 (AL)发生、发展及预后的关系。用聚合酶链反应 (PCR)、DNA单链构象多态性 (SSCP)分析和DNA测序技术研究 5 3例初治和复发儿童AL及 30例对照组p1 6基因纯合子缺失和点突变的情况。结果 :儿童ALp1 6基因纯合子缺失及点突变为 2 8.30 % (1 5 /33例 ) ,对照组未发现缺失及突变。ALL组p1 6基因纯合子缺失为 35 .0 0 % (1 4/4 0例 ) ,其中HR—ALL为 47.0 6 % (8/1 7例 ) ,SR—ALL8.33% (1 /1 2例 ) ,复发ALL为 45 .45 % (5 /1 1例 ) ,未见点突变 ;ANLL组未见纯合子缺失 ,点突变 1例 ,为 7.6 9% (1 /1 3例 ) ,测序分析发现其位于第 2外显子 (exon2A) 49密码子 ,发生错义突变 ,由GCC突变为ACC ,由苏氨酸取代丙氨酸。结果表明 :①p1 6基因失活与儿童AL ,尤其与儿童ALL的发生、发展关系密切。②在儿童ALL中 ,p1 6基因纯合子缺失是基因失活的主要形式 ,点突变罕见。③在儿童ANLL中 ,p1 6基因纯合子缺失、点突变均罕见。④p1 6基因失活可能成为预测儿童AL病程进展、复发、预后的指标之一。

STUDIES ON p16 GENE HOMOZYGOUS DELETION AND POINT MUTATION IN CHILDHOOD WITH ACUTE LEUKEMIA

Objective: To explore the correlation between homozygous deletions and mutation of p16 gene and the development, progression and prognosis of childhood with acute leukemia (AL). Methods: p16 gene homozygous deletions and point mutation in 53 case with primary and relepse childhood AL and 30 controls were investigated with polymerase chain reaction (PCR), DNA single strand conformation polymorphism (SSCP) and DNA sequencing. Results: The p16 gene homozygous deletions and point mutation were found in 28.30%(15/53) of AL case, and none of all controls. Homozygous deletions were found in 35.00%(14/40), 47.06%(8/17), 8.33%(1/12), 45.45%(5/11) and 0%(0/13) of all ALL, HR-ALL, SR-ALL, relapse-ALL and ANLLcases, respectively. The point mutation wasn't found in ALL cases, while was found in 1 case (7.69%) of 13 ANLL cases. Sequencing analysis showed that the nucleotide change in exon 2A was a missense mutation from GCC (Ala) to ACC (Thr). Conclusion: ①There was a close correlation between p16 gene inactiviation and the development of childhood with AL, especially ALL. ②p16 gene homozygous deletion is a main way of inactiviation, while point mutation was rare in ALL. ③Both p16 gene homozygous deletion and point mutation were rare in ANLL. ④p16 gene inactivation may be used as a parameter for casing progression, progression, relapse and prognosis.