ASS为精氨基琥珀酸合成酶的编码基因，称为精氨基琥珀酸合成基因,位于第9q34.1，和ABL基因相距大约200kb,全长56kb,有13-16个编码的外显子。
|
疾病名称 |
检测探针 |
标记颜色 |
探针定位 |
探针名称 |
|
慢性粒细胞性
白血病（CML） |
GLP ASS |
红 |
9q34 |
ASS 基因异常检测试剂盒
（荧光原位杂交法） |
【临床意义】
CML是一种骨髓多能造血干细胞的恶性肿瘤，在白血病中约占20%～25%，其发病过程分慢性期、加速期和恶变期，病程3～4年[1]。
9-28％CML患者伴有含有ASS基因的9q34区段的缺失[2]。ASS位于ABL附近，该基因缺失的患者此种患者预后差，慢性期易急变。因此，检测CML患者骨髓中ASS基因状况可以：
1. 有ASS基因缺失的患者，生存期显著缩短[5]
2. 用干扰素单独治疗的患者，缺失状态可以作为对药物的应答率、慢性期的长短和总生存期的有用预后指标[2-4]。
3. 对于自体异基因骨髓移植患者，有缺失的患者复发率显著增加（P<0.001），而且有缺失的患者在1年内的复发率特别高，但未缺失的患者在1年内不复发[6] 。
4. 慢性期和大部分的加速期的患者中缺失状态的患者血液学和细胞遗传学反应统一较低，慢性期或者加速期缺失型患者用磺酸伊马替尼治疗后的无疾病进展生存期（Progression-free survival）显著性缩短[7]。
【参考文献】
[1] 陈赛娟。血液急性疾病基因异常和靶向治疗。上海科学技术出版社，P206.
[2] Stephanie A. Smoley, Stephanie R. Brockman, Sarah F. Paternoster, Reid G. Meyer,Gordon W. Dewald. A novel tricolor, dual-fusion fluorescence in situ hybridization method to detect BCR/ABL fusion in cells with t(9;22)(q34;q11.2) associated with deletion of DNA on the derivative chromosome 9 in chronic myelocytic leukemia. Cancer Genetics and Cytogenetics. 2004; 148: 1–6.
[3] Huntly B, Reid A, Bench A, et al. Deletions of the derivative chromosome 9 occur at the time of the Philadelphia translocation and provide a powerful and independent prognostic factor in chronic myeloid leukaemia. Blood. 2001;98:1732-1738.
[4] Brian J. P. Huntly, Anthony Bench, and Anthony R. Green. Double jeopardy from a single translocation: deletions of the derivative chromosome 9 in chronic myeloid leukemia. Blood. 2003;102:1160-1168.
[5] Sinclair PB, Nacheva EP, Laversha M, et al.Large deletions at the t(9; 22) breakpoint are common and may identify a poor-prognosis subgroup of patients with chronic myeloid leukaemia. Blood. 2000;95:738-744.
[6] Kolomietz E, Al-Maghrabi J, Brennan S, et al. Primary chromosomal rearrangements of leukemia are frequently accompanied by extensive submicroscopic deletions and may lead to altered prognosis.Blood. 2001;97:3581-3588.
[7] Huntly BJ, Guilhot F, Reid AG, et al. Imatinib improves but may not fully reverse the poor prognosis of CML patients with derivative chromosome 9 deletions. Blood. Prepublished on May 15, 2003, as DOI 10.1182/blood-2002-09-2763.