Department of Pathology, National Taiwan University Hospital, Taipei, Taiwan.
Histopathology. 2011 May;58(6):896-905. doi: 10.1111/j.1365-2559.2011.03793.x. Epub 2011 Mar 14.
Extramedullary plasmacytoma (EMP) and multiple myeloma (MM) are both plasma cell (PC) tumours that are usually distinguished by clinical manifestations, but not by histopathological examination alone. However, EMP may express B-cell markers, such as CD79a and CD20, and MM may express germinal centre B-cell (GCBC)-associated microRNAs, such as miR-93 and miR-181b. Down-regulation of miR-30a or up-regulation of miR-223 is associated with the transition from GCBCs into PCs or memory B-cells, respectively. We studied B-cell markers and microRNAs to establish criteria that could distinguish EMP from MM.
Immunostains for the B-cell markers CD19, CD20, CD79a and PAX5 were performed. Expression levels of microRNAs 30a, 93, 181b and 223 were measured by real-time reverse transcription polymerase chain reactions. 73% of EMPs expressed CD19 whereas MM cases were negative. EMP and MM had similar levels of miR-30a, miR-93, and miR-181b, but EMP lacked expression of miR-223.
The presence of CD19 and lack of miR-223 suggested aberrant B-cell differentiation in EMP. Although the underlying mechanism for this differential expression was unclear, a CD19(+) /miR-223(-) phenotype could be used to distinguish EMP from the CD19(-) /miR-223(+) phenotype of MM.
髓外浆细胞瘤（EMP）和多发性骨髓瘤（MM）均为浆细胞（PC）肿瘤，其通常通过临床表现区分，但仅凭组织病理学检查无法区分。然而，EMP 可能表达 B 细胞标志物，如 CD79a 和 CD20，而 MM 可能表达生发中心 B 细胞（GCBC）相关的 microRNAs，如 miR-93 和 miR-181b。miR-30a 的下调或 miR-223 的上调分别与 GCBC 向 PCs 或记忆 B 细胞的转化有关。我们研究了 B 细胞标志物和 microRNAs，以建立可将 EMP 与 MM 区分开来的标准。
进行了 B 细胞标志物 CD19、CD20、CD79a 和 PAX5 的免疫染色。通过实时逆转录聚合酶链反应测量 microRNAs 30a、93、181b 和 223 的表达水平。73%的 EMP 表达 CD19，而 MM 病例为阴性。EMP 和 MM 具有相似水平的 miR-30a、miR-93 和 miR-181b，但 EMP 缺乏 miR-223 的表达。
CD19 的存在和 miR-223 的缺失提示 EMP 中存在 B 细胞分化异常。尽管这种差异表达的潜在机制尚不清楚，但 CD19(+) / miR-223(-) 表型可用于将 EMP 与 MM 的 CD19(-) / miR-223(+) 表型区分开来。
