急性T淋巴细胞白血病中SIL-TAL1融合基因与6q缺失的相关性研究

Correlation between Expression of SIL-TAL1 Fusion Gene and Deletion of 6q in T-cell Acute Lymphoblastic Leukemia

本研究旨在探讨SIL-TAL1融合基因在急性T淋巴细胞白血病(T-ALL)患者中的表达情况,分析伴有SILTAL1阳性的T-ALL患者的临床和细胞遗传学特征。运用巢式逆转录聚合酶链反应检测68例T-ALL患者骨髓标本中的SIL-TAL1的表达,以R显带核型分析和微阵列比较基因组杂交检测核型异常。结果表明:在12例T-ALL患者中检测到SIL-TAL1融合基因的表达,儿童检出率明显高于成人(38.5%vs 4.8%,P=0.001),其中50%(6/12)SIL-TAL1阳性患者存在两种转录本;SIL-TAL1阳性组核型异常率为54.5%(6/11),其中4例伴有6号染色体长臂大片段缺失;2例经array-CGH检测到1p32存在约90 kb的缺失,形成SIL-TAL1融合基因;6号染色体长臂共同缺失区域为6q14.1-q16.3,均为杂合性缺失;SIL-TAL1阳性组中位白细胞计数和乳酸脱氢酶水平均高于阴性组(P<0.05)。结论:SIL-TAL1融合基因与6q杂合性缺失有一定相关性(P=0.005),在儿童中SIL-TAL1的检出率明显高于成人,且常伴有白细胞计数升高、乳酸脱氢酶升高等不良预后因素。

The present study was designed to investigate the prevalence and clinical significance of SIL-TAL1 rearrangements in T-cell acute lymphoblastic leukemia（ T-ALL）.The incidence of SIL-TAL1 rearrangements was analyzed by nest real-time quantitative polymerase chain reaction（ RT-PCR）in 68 patients with T-ALL.Karyotypic analysis was performed by conventional R-banding assay and array-based comparative genomic hybridization（ array-CGH）.The results showed that SIL-TAL1 rearrangements were identified in 10 /26（ 38.5）%pediatric and 2 /42（ 4.8）%adult T-ALL caseswhich indicate a pediatric preference for SIL-TAL1 rearrangements in T-ALL.Two different transcripts were detected in 6 /12（50%）T-ALL samples.Abnormal karyotypes were detected in 6 out of 11 cases（ 54.5%and a deletion of the long arm of chromosome 6 was observed in 4 cases.Array-CGH results of 2 T-ALL cases with SIL-TAL1 rearrangement revealed that this fusion gene was resulted from a cryptic deletion of 1p32 and the overlap region of 6q deletion was 6q14.1-16.3.These cases with SIL-TAL1 fusion had a higher white blood cell（ WBC）count and higher serum levels of lactate dehydrogenase（LDH）than cases without SIL-TAL1 fusion.It is concluded that SIL-TAL1 rearrangements are associated with loss of heterozygosity of chromosomal 6qand SIL-TAL1 positive patients are younger than SILTAL1 negative patients.In contrast to the cases without SIL-TAL1 fusionthere are many adverse prognostic factors in the cases with SIL-TAL1 fusionsuch as higher WBC count and higher LDH levels.