Zhang X Y, Ma Z P, Cui W L, Chen R, Glinaer Abulajiang, Miao N, Li X X
Department of Pathology, the First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, China.
Zhonghua Bing Li Xue Za Zhi. 2016 Dec 8;45(12):831-837. doi: 10.3760/cma.j.issn.0529-5807.2016.12.004.
To investigate PRDM1 gene methylation status, immune classification and their prognostic significance in diffuse large B cell lymphoma (DLBCL). Immunohistochemical (IHC) staining for CD20, CD10, bcl-2, bcl-6, PRDM1/Blimp-1 and MUM1 was carried out in 100 cases of DLBCL specimens and 20 reactive lymphoid proliferation samples. All patients were classified into germinal center B cell-like (GCB) and activated B cell-like (ABC) subtype according to Hans' algorithmin. PRDM1 gene methylation was detected by methylation-specific PCR (MSP) and its relationship with clinicopathologic parameters was analyzed. OCI-Ly1 (GCB type) and OCI-Ly3 (ABC type) cell lines were transfected by Small interfering RNA(siRNA) with cationic lipid reagent transfection mediated, and the PRDM1/Blimp-1 expression in before and after transfected cell lines were detected with reverse transcription-PCR and Western blot methods. The relationship between PRDM1 gene methylation, clinicopathologic parameter and survival was analyzed using one-way analysis of variance. One hundred patients were classified into 73 (73%) cases of GCB subtypes and 27 (27%) cases of ABC. PRDM1/Blimp-1 was expressed in 21 DLBCL and highly expressed in 20 reactive lymphoid proliferation. PRDM1 gene methylation was detected in 23% (23/100) of DLBCL, while no methylation was detected in all 20 reactive lymphoid proliferation. The difference of the PRDM1 methylation status between DLBCL and the control samples was statistically significant (=0.004). However, there was no significant correlation between the PRDM1 gene methylation and clinicopathologic parameters (>0.05). Reverse transcription-PCR and Western blot showed that PRDM1 gene expression was reduced in siRNA-induced group compared with blank control group and negative control group. One-way analysis of variance revealed that aged ≥60 years, performance status score above 3, and the presence of general symptoms were associated with significantly lower overall survival rate. PRDM1 gene silencing with aberrant CpG methylation is probably one of the critical events in the oncogenesis of DLBCL. This may have important implications as a candidate marker for diagnosis and targeted gene therapy. Meanwhile in vitro siRNA transfected OCI-Ly1 and OCI-Ly3 cell lines confirm that PRDM1 gene is a suppressor gene in DLBCL and may represent a novel therapeutic target.
探讨PRDM1基因甲基化状态、免疫分型及其在弥漫性大B细胞淋巴瘤（DLBCL）中的预后意义。对100例DLBCL标本和20例反应性淋巴组织增生样本进行CD20、CD10、bcl-2、bcl-6、PRDM1/Blimp-1和MUM1的免疫组织化学（IHC）染色。根据汉斯算法将所有患者分为生发中心B细胞样（GCB）和活化B细胞样（ABC）亚型。采用甲基化特异性PCR（MSP）检测PRDM1基因甲基化，并分析其与临床病理参数的关系。通过阳离子脂质试剂介导的小干扰RNA（siRNA）转染OCI-Ly1（GCB型）和OCI-Ly3（ABC型）细胞系，采用逆转录-PCR和蛋白质免疫印迹法检测转染前后细胞系中PRDM1/Blimp-1的表达。采用单因素方差分析PRDM1基因甲基化、临床病理参数与生存之间的关系。100例患者中，GCB亚型73例（73%），ABC亚型27例（27%）。PRDM1/Blimp-1在21例DLBCL中表达，在20例反应性淋巴组织增生中高表达。23%（23/100）的DLBCL检测到PRDM1基因甲基化，而20例反应性淋巴组织增生中均未检测到甲基化。DLBCL与对照样本的PRDM1甲基化状态差异有统计学意义（P=0.004）。然而，PRDM1基因甲基化与临床病理参数之间无显著相关性（P>0.05）。逆转录-PCR和蛋白质免疫印迹显示，与空白对照组和阴性对照组相比，siRNA诱导组PRDM1基因表达降低。单因素方差分析显示，年龄≥60岁、体能状态评分高于3分以及存在全身症状与总生存率显著降低相关。PRDM1基因因异常的CpG甲基化而沉默可能是DLBCL肿瘤发生的关键事件之一。这可能作为诊断和靶向基因治疗的候选标志物具有重要意义。同时，体外siRNA转染OCI-Ly1和OCI-Ly3细胞系证实PRDM1基因是DLBCL中的抑癌基因，可能代表一种新的治疗靶点。
