弥漫大B细胞淋巴瘤患者血浆shp1基因甲基化检测及其意义

Plasma DNA methylation of shp1 in patients with diffuse large B cell lymphoma

目的：探讨弥漫大B细胞淋巴瘤（ DLBCL ）患者血浆shp1基因甲基化状态及其临床意义。方法选取2012年1月至2013年12月天津医科大学总医院血液科收治的35例初治DLBCL患者，用甲基化特异性聚合酶链反应（ MSP）方法分别检测患者血浆、外周血白细胞（ PBL）和其中28例对应福尔马林固定石蜡包埋（ FFPE）肿瘤组织中shp1甲基化，同时以6例良性淋巴组织增生和13名健康志愿者作为对照。比较各组间3种标本中shp1基因甲基化频率，分析shp1基因甲基化状态与患者临床病理指标的相关性。结果19例对照组中均未检测到shp1基因甲基化；DLBCL患者血浆、PBL、FFPE组织中 shp1基因甲基化检出率分别为51.4％（18／35）、28.6％（10／35）、64.3％（18／28）。 shp1基因甲基化在血浆和FFPE组织中有较高的一致性（κ＝0.78，P＝0.00），在PBL和FFPE组织中一致性较低（κ＝0.36，P＝0.01）。高血清乳酸脱氢酶（LDH）的患者血浆和FFPE组织中shp1基因甲基化检出率高于LDH正常患者（13／16比5／19，11／12比7／16，P＝0.02、0.04），患者PBL中shp1基因甲基化检出率与血清LDH水平无关（ P＝0.14）。结论 DLBCL患者血浆shp1基因甲基化状态能较好地反映肿瘤组织中shp1基因甲基化状态，有望成为辅助DLBCL诊断、指导靶向治疗的相对无创的生物学指标。

Objective To explore the methylation status of shp 1 gene in plasma DNA from patients with diffuse large B cell lymphoma （ DLBCL） and discuss its possible application in molecular diagnosis and targeted therapy of the disease.Methods Methylation-specific polymerase chain reaction （ MSP） was used to detect the methylation status of shp 1 gene in plasma and peripheral blood leukocytes （ PBLs） of 35 DLBCL patients.The formaldehyde-fixed, paraffin-embedded （ FFPE） tumor tissue samples were collected from 28 DLBCL patients , 6 patients of benign lymphoid hyperplasia and 13 healthy volunteers were selected as nonmalignant controls from January 2012 to December 2013.Methylation frequencies of shp 1 gene in different groups were compared and the associations of shp 1 methylation status with clinicopathological characteristics were analyzed.Results No methylation of shp1 was detected in any of the 19 nonmalignant controls.The methylation rate of shp1 in plasma, PBLs and FFPE tumor tissues from patients with DLBCL was 51.4%（18/35）, 28.6%（10/35） and 64.3%（18/28） respectively; there was a high methylation consistency of shp1 between plasma and FFPE tumor tissues （κ=0.78, P=0.00）.However, methylation consistency was lower between PBLs and FFPE tumor tissues （κ=0.36, P=0.01）.Methylation of shp1 was frequently detected in plasma and FFPE tumor tissues samples from patients with a high serum level of lactate dehydrogenase （13/16 vs 5/19,11/12 vs 7/16,P=0.02, 0.04）.However, no such association was detected＆amp;nbsp;in PBLs（P =0.14）.Conclusions Methylation of shp1 in plasma DNA can represent shp1 methylation status in tumor tissue.And it may serve as a promising biomarker in aiding DLBCL diagnosis and guiding targeted therapy.