摘要
FHIT基因位于染色体 3p14 .2 ,实验室的研究证实FHIT基因具有抑癌基因活性。FHIT基因异常表达或表达缺失出现在多种实体肿瘤和造血系统恶性疾病。为了探讨白血病细胞中FHIT基因的异常表达及意义 ,采用巢式RT PCR法对急性髓性白血病 (AML)、急性淋巴细胞白血病 (ALL)、慢性粒细胞白血病 (CML)以及骨髓增生异常综合症 (MDS)、慢性淋巴细胞白血病 (CLL)、骨髓瘤 (MM )等不同类型白血病患者FHIT基因转录本进行检测 ,并对FHIT基因转录本进行序列测定。 98份血液系统恶性疾病患者的骨髓或外周血标本中AML 38例 ,ALL16例 ,CML 34例 ,其它恶性血液病 10例。全部患者经骨髓细胞形态检查 ,诊断符合FAB诊断标准。肝素抗凝骨髓或外周血 2 - 3ml,分离单个核细胞 ,取 5× 10 7个细胞 ,用RTIZOL 试剂一步法提取细胞总RNA ,行PCR扩增 ,琼脂糖凝胶电泳分析PCR产物。回收目的片段 ,克隆到PGEM T载体 ,进行序列测定。结果表明 :在 5 5 / 98(5 6 % )的被检测病例有FHIT基因的异常表达 ,在AML、ALL和CML异常表达的发生率分别为 2 2 / 38(5 8% ) ,9/ 16(5 6 % )和 19/ 34(5 6 % )。正常骨髓或外周血标本未见有FHIT基因的异常表达。 4 3/ 98(44 % )的患者表达正常转录本 (Ⅰ型 ) ,4 0 / 98(41% )
FHIT (fragile histidine triad) gene at chromosome 3p14.2 usually expresses at a very low level in human tissue and cells. A high frequency of abnormalities in FHIT gene has been demonstrated in various cancers. FHIT is proposed as a putative tumor suppressor gene. To evaluate the expression of the FHIT gene in various leukemias, bone marrow or peripheral blood samples from 98 leukemia patients were tested by RT PCR: 38 from patients with AML [M 2(9), M 3(12), M 4(8), M 5(9)], 16 with ALL, and 34 with CML [CP(20), AP(4), BC(10)] of various FAB types, as well as 10 patients with other hematological malignancies. To detect a deletion in sequencing the FHIT gene, the representative aberrant PCR products were cloned and then sequenced. The results showed that 22/38 (58%) patients with AML, 9/16 (56%) patients with ALL and 19/34 (56%) patients with CML were detectable of aberrant FHIT mRNA transcripts or deletion of FHIT. In 6 (16%) AML patients, 3 (19%) ALL patients, and 5 (15%) CML patients, the wild type product was absent. Some patient′s samples -- 6 (42%) AML, 6 (38%) ALL, and 14 (41%) CML revealed aberrant FHIT transcripts in addition to a normal sized band. Samples from healthy donors (PB, n=12; BM, n=5) did not indicate any abnormal expression. Eleven isolated fragments from various patterns of FHIT gene expression were investigated using cDNA sequencing. Sequence analysis revealed deletion of exon 4-8, exon 5-8, and exon 5-6 in various leukemias, as well as the deletion of the full FHIT gene sequence. The fused transcripts included: exon 3 and exon 9, exon 3 and exon 7, exon 4 and exon 9, exon 5 and exon 7. Sequence analysis of aberrant fragments present in samples from an AML and a CML patients was detected for point mutations and insert mutations located in exons 2, 8 and 10, plus a variety of aberrant transcripts. Deletion or aberrant FHIT mRNA transcripts in 50/98 (51%) leukemia patients were found. All samples with aberrant FHIT lacked gene product. A Kaplan Meier plot of survival in patients with AML in relation to FHIT expression revealed that aberrance or loss of FHIT gene significantly correlated with a low clinical remission rate and poor overall survival.
出处
《中国实验血液学杂志》
CAS
CSCD
2003年第2期153-160,共8页
Journal of Experimental Hematology
基金
ThisstudywassupportedbyagrantfromtheResearchPromotionFundationofTheInstituteofBasicMedicalSciencesbetween 1999-2 0 0 1
