Objective To investigate the methylation status of LRP15 gene in acute leukemia (AL) patients and its role in the tumorigenesis. Methods The methylation of LRP15 promoter and first exon of bone marrow mononuclear cells in 73 patients with AL, 10 with chronic leukemia (CL), 9 with hematological benign diseases, and 20 healthy transplantation donors was analyzed by using methylation specific polymerase chain reaction. The methylation of LRP15 gene promoter and first exon in COS7, K562, and HL60 cell lines was also assayed. Results No LRP15 gene promoter methylation was detected in COS7 cell line. LRP15 gene promoter was methylated in K562 and HL60 cell lines. No deletion of LRP15 gene was detected in all samples. In nearly all French-American-British leukemia subtypes, we found that frequency of LRP15 methylation in adult patients with AL was 71.23% (52/73). There was no detectable methylation in any of the 20 healthy donors and 8 chronic myeloid leukemia patients. The difference in frequency of LRP15 methylation between AL patients and healthy donors or CL patients (10.00%, 1/10) was significant (P<0.01). Hypermethylation of LRP15 gene was found in 57.14% (16/28) of newly diagnosed AL patients, 83.33% of relapsed AL patients respectively, which was significantly different (P<0.05). We also demonstrated LRP15 methylation in 55.56% (5/9) adults with benign hematological diseases. Conclusions LRP15 methylation changes are common abnormalities in leukemia. LRP15 is postulated to be a tumor suppressor gene.
Li-ping Dou Chang Wang Zhou-min Xu Hui-yuan Kang Hui Fan Fang-ding Lou Li Yu
目的探讨 Id4基因甲基化作为检测急性白血病(AL)微量残留病变指标的可行性。方法采用甲基化特异性聚合酶链反应(MS-PCR)技术对细胞系中不同比例的白血病细胞以及正常人、初诊和完全缓解期的 AL 患者骨髓进行 Id4基因甲基化状态检测。结果 MS-PCR 方法可在低于1%白血病细胞中检测到Id4基因甲基化。Id4基因在正常骨髓中呈完全性非甲基化状态,初治急性髓系白血病(AML)和急性淋巴细胞白血病(ALL)患者中甲基化比例分别为84%和86%。Id4基因在完全缓解的 ALL 患者中甲基化比例达60.9%,高于完全缓解状态的 AML 患者。Id4基因甲基化检测阳性的14例 ALL 患者中有8例在12个月内复发,而甲基化检测阴性的9例 ALL 患者仅有1例复发。Id4基因呈甲基化状态的8例 AML 患者中有5例在12个月内复发,而 Id4基因呈非甲基化的20例 AML患者中12个月内仅有2例复发。结论 MS-PCR 检测 Id4基因甲基化有可能作为 AL 微量残留病的检测方法。
