不同部位黏膜相关淋巴组织结外边缘区B细胞淋巴瘤中染色体的异常及其意义

目的 探讨不同部位黏膜相关淋巴组织结外边缘区B细胞淋巴瘤(MALT淋巴瘤)中t(11;18)/APl2-MALT1、t(1;14)/IgH-bcl-10、t(14;18)/IgH-MALT1和其他遗传学异常的发生情况及其意义.方法 收集196例不同部位的MALT淋巴瘤,包括胃53例[其中9例有弥漫性大B细胞淋巴瘤(DLBCL)成分]、眼眶50例、涎腺20例、肺20例、肠17例、皮肤17例、肝脏8例、甲状腺5例和其他部位6例(包括舌根2例,胰腺、喉、声带和肾脏各1例),用荧光原位杂交(FISH)分别检测APl2-MALT1、bel-10、MALT1和IgH基因的异常.结果 在196例MALT淋巴瘤中,APl2-MALT1融合基因共检出25例(12.8%).但是在不同部位,阳性率差异有统计学意义(P=0.002):从高到低依次为肺(45.0%,9/20)、不伴DLBCL成分的胃MALT淋巴瘤(22.7%,10/44)、涎腺(15.0%,3/20)、肠2/17、眼眶2.0%(1/50).而在伴DLBCL成分的胃MALT淋巴瘤、皮肤、甲状腺、肝脏和其他散发部位均未发现APl2-MALT1融合基因.在196例中,1例肺MALT淋巴瘤同时显示IgH基因和MALT1基因异常,可能是t(14;18)/IgH-MALT1异常.3例(2例不伴DLBCL成分的胃和1例肺)同时显示IgH基因和bcl-10基因异常,可能是t(1;14)/IgH-bcl-10异常.此外,用MALT1基因探针检测中,6例(2例涎腺、2例肝脏、1例伴DLBCL成分的胃和1例甲状腺)可能为18号染色体3体;3例(2例胃和1例肠)为MALT1基因扩增.结论 在MALT淋巴瘤中特异性的染色体异常发生率较低,但在不同部位,这些异常发生率存在差异.该现象提示发生在不同部位的MALT淋巴瘤,尽管组织形态学特点类似,但可能具有不同的发病机制.

Frequency of genetic aberrations in mueesa-assoelated lymphoid tissue lymphoma of different sites

Objective To study the frequency of certain specific genetic aberrations, including t(11;18)/API2-MALT1, t(1;14)/IgH-I-bcl-10 and t(14;18)/IgH-I-MALT1, in mucosa-associated lymphoid tissue (MALT) lymphoma of different sites. Methods One hundred and ninety-six cases of MALT lymphoma from Cancer Hospital of Fudan University were enrolled into the study. The samples consisted of MALT lymphomas from stomach (53 cases, including 44 cases of low-grade MALT lymphoma and 9 cases of MALT lymphoma with diffuse large B-cell lymphoma component), ocular adnexa (50 cases), salivary gland (20 cases), lung (20 cases), intestine (17 cases), skin (17 cases), liver (8 cases), thyroid (5 cases) and other sites (2 cases from tongue, 1 ease from pancreas, 1 case from larynx, 1 case from vocal cords and 1 case from kidney). Fluorescence in-situ hybridization for API2-MALT1 fusion gene, bcl-1O, MALT1 and IgH genes was performed on paraffin sections. Results Among the 196 cases of MALT lymphoma, 25 cases (12. 8%) possessed API2-MALTI fusion gene. The positive rates in various sites were significantly different (P=0.002), as follows: 45.0% (9/20) in lung, 22. 7%(10/44) in stomach (without large cell component), 15.0%(3/20) in salivary gland, 2 of 17 cases in intestine and 2.0% (1/50) in ocular adnexa. The fusion gene was not detected in the 9 cases of gastric MALT lymphoma with large cell transformation. It was also negative in the MALT lymphomas from skin, thyroid and other sites. One of the pulmonary MALT lymphoma cases showed simultaneous aberrations of IgH and MALT1 genes, such as t(14;18)/IgH-MALT1. Two of the gastric MALT lymphoma cases without large cell transformation and one ofthe pulmonary MALT lymphoma cases showed aberrations in both IgH and bcl-10 genes,such as t(1;14)/IgH-bcl-10.Six cases of MALT lymphoma,including 2 cases from salivary gland,2 cases from liver,1 case from thyroid and 1 case from stomach(large cell transformation),showed trisomy 18.On the other hand,3 cases,including 2 cases from stomach and 1 case from intestine,showed MALT1 gene amplification.Condusions In general,specific genetic aberrations have a relatively low frequency of occurrence in MALT lymphomas.The positive rates however show a remarkable difference in tumors of different anatomic sites.This phenomenon may suggest that MALT lymphomas in different sites,though sharing similar morphologic features,may have a divergent tumorgenesis.