胃肠道黏膜相关边缘区B细胞淋巴瘤和弥漫性大B细胞淋巴瘤中API2-MALT1融合基因表达的差异

Prevalence of API2-MALT1 fusion gene in gastrointestinal mucosa-associated lymphoid tissue lymphomas and diffuse large B cell lymphomas

目的比较t（11；18）（q21；q21）／API2-MALT1融合基因在胃肠道黏膜相关边缘区B细胞淋巴瘤（MALT淋巴瘤）和弥漫性大B细胞淋巴瘤（DLBCL）中的发生情况，探讨t（11；18）（q21；q21）与胃肠道MALT淋巴瘤和DLBCL间演进的关系。方法收集57例胃肠道MALT淋巴瘤（包括38例胃和19例肠），32例胃肠道DLBCL（包括28例胃和4例肠）和7例胃DLBCL同时合并MALT淋巴瘤成分，用荧光原位杂交（FISH）检测API2-MALT1融合基因。使用的探针包括API2-MALT1双色融合易位探针和MALT1双色分离重排探针。结果在MALT淋巴瘤中有21．1％（12／57，包括10例胃和2例肠）发现API2-MALT1融合基因，而在32例DLBCL和7例DLBCL与MALT淋巴瘤混合的病例中均未检测出API2-MALT1融合基因。两组经统计学比较差异有统计学意义（x^2=9．383，P=0．001）。结论API2-MALT1融合基因是MALT淋巴瘤中特异的遗传学异常，而不见于DLBCL或DLBCL与MALT淋巴瘤共存的病例中，提示至少在胃肠道API2-MALT1阳性的MALT淋巴瘤一般不会发生大细胞转化，而胃肠道DLBCL可能为原发或由t（11；18）阴性的部分MALT淋巴瘤转化而来。

Objective To investigate the difference of the prevalence of t （ 11 ; 18 ） （ q21 ; q21 ）/ API2-MALT1 fusion geue between gastrointestinal mucosa-associated lymphoid tissue （MALT） lymphoma and diffuse large B cell lymphoma （ DLBCL ） . Methods A total of 57 cases gastrointestinal MALT lymphomas （38 gastric and 19 intestinal lymphomas）, 32 DLBCL （28 gastric and 4 intestinal lymphomas ） and 7 cases gastric DLBCL accompanied MALT lymphoma were collected from the Cancer Hospital of Fudan University. API2-MALT1 fusion gene was detected by fluorescent in situ hybridization （FISH） using both dual fusion translocation and break apart probes. Results Among gastrointestinal MALT lymphomas, API2- MALT1 fusion gene was found in 12 of 57 cases （21.1% , 10 gastric and 2 intestinal lymphomas）. In contrast, the fusion gene was not found in all 32 DLBCL and 7 gastric DLBCL with MALT lymphoma component. There was statistical significant difference between two groups （ x^2 = 9. 383, P = 0. 001 ） . Conclusions API2-MALT1 fusion gene is a distinctive genetic aberration in MALT lymphomas, and is not present in DLBCL. The findings suggest that gastrointestinal tract MALT lymphomas with API2-MALT1 fusion gene may not transform into DLBCL, which may represent primary lymphoma or transformed API2- MALT1 negative MALT lymphomas.