Molecular and Clinicopathologic Significance of Gene Alteration Associated with MALT Lymphoma

API 2-MALT 1融合基因是从t（11;18）（q21;q21）染色体易位中克隆到的一种粘膜相关淋巴组织（MALT）结边缘区B细胞淋巴瘤特异性基因异常。然而，这种嵌合基因的临床病理意义仍有待澄清。我们已经开发了一个非常敏感的多重RT-PCR检测API 2-MALT 1融合转录物使用石蜡材料作为RNA的来源，并使这种基因异常的大型队列研究。我们的一个大系列的肺MALT淋巴瘤的数据表明，API 2-MALT 1融合可能是一个致病基因异常无关的自身免疫性疾病。此外，这种改变可以定义一个同质的MALT淋巴瘤亚型，临床上更惰性和组织学上更“典型”。从胸腺MALT淋巴瘤研究中获得的数据进一步支持了我们的观察，即API 2-MALT 1融合不依赖于自身免疫性疾病。异常的核BCL 10表达可能作为一种工具，以筛选这种API 2-MALT 1融合在肺MALT淋巴瘤，但这不是皮肤MALT淋巴瘤的情况。罕见的食管和输尿管MALT淋巴瘤的情况下，已报告。

API2-MALT1 fusion gene, cloned from t(11;18)(q21;q21) chromosomal translocation, is a gene abnormality specific to extranodal marginal zone B-cell lymphoma of mucosal-associated lymphoid tissue (MALT). However, the clinicopathologic significance of this chimeric gene remains to be clarified. We have developed a very sensitive multiplex RT-PCR assay for the API2-MALT1 fusion transcript using paraffin materials as a source of RNA, and enabled a large cohort study on this gene abnormality. Our data of a large series of pulmonary MALT lymphoma suggest that the API2-MALT1 fusion may be a causative gene abnormality unrelated to autoimmune disease. In addition, this alteration may define a homogeneous MALT lymphoma subtype that is clinically more indolent and histologically more "typical". Our observation that API2-MALT1 fusion is independence of autoimmune disease is further supported by the data obtained from the study of thymic MALT lymphoma. Aberrant nuclear BCL10 expression may have a possible role as a tool to screen for this API2-MALT1 fusion in pulmonary MALT lymphoma, but this is not the case with cutaneous MALT lymphoma. Case of rare esophageal and ureteral MALT lymphomas have been reported.