儿童侵袭性成熟B细胞淋巴瘤的临床病理学及分子遗传学特点

目的 分析总结中国儿童各类型侵袭性成熟B细胞淋巴瘤的临床病理学及分子遗传学特点,为其诊断的标准化提供依据.方法 收集97例儿童侵袭性成熟B细胞淋巴瘤石蜡包埋组织标本,包括伯基特淋巴瘤(BL)81例、弥漫大B细胞淋巴瘤(DLBCL)8例、介于BL和DLBCL间的不能分类的B细胞淋巴瘤(BL/DLBCL)8例,利用免疫组织化学技术和间期荧光原位杂交(FISH)技术检测其免疫表型和分子遗传学特征.结果 BL的bcl-2和MUM1的阳性率分别为3%(2/66)和17%(12/71),DLBCL分别为50%(4/8)和63%(5/8),BL/DLBCL分别为50%(4/8)和63%(5/8).BL、DLBCL和BL/DLBCL的Ki-67平均值分别为(93±4.4)%、(83±14.3)%和(80±11.5)%.BL、DLBCL和BL/DLBCL的c-myc基因易位的比例分别为98%(79/81)、38%(3/8)和50%(4/8).38%(3/8)的DLBCL和25%(2/8)的BL/DLBCL存在bcl-6基因的多拷贝,BL与DLBCL之间、BL与BL/DLBCL之间bcl-2、MUM1和Ki-67平均值的差异及c-myc基因易位和bcl-6基因多拷贝的差异均有统计学意义(均P＜0.05).结论 儿童侵袭性成熟B细胞淋巴瘤的诊断和分型需要综合分析形态学、免疫表型和分子遗传学特征.儿童BL/DLBCL可能是DLBCL的一个亚型.CD10+、bcl-6+、bcl-2-、Ki-67＞90%、伴有IGH/c-myc重排、不伴有bcl-2和bcl-6重排时,支持BL的诊断;bcl-2+、Ki-67为50%～90%,同时伴有bcl-6基因的多拷贝时,支持DLBCL或BL/DLBCL的诊断.

Clinicopathologic and molecular genetics features of mature aggressive B-cell lymphomas in pediatrics

Objective To investigate the immunophenotype and molecular genetics of mature aggressive B-cell lymphomas in Chinese pediatric patients and provide the criteris for the diagnosis of them.Methods We collected 97 paraffin-embeded tissue samples of pediatric cases of mature aggressive B-cell lymphomas including 81 Burkitt lymphoma (BL) cases, 8 diffuse large B cell lymphoma (DLBCL) cases and 8unclassifiable B cell lymphoma with featares intermediate between BL and DLBCL (BL/DLBCL) cases. The immunophenotype and genetic features of them were detected by immunohistochemistry and interphase FISH.Results The expression of bcl-2 [3 %(2/66) in BL, 50 % (4/8) in DLBCL, 50 % (4/8) in BL/DLBCL], MUM1 [17 % (12/71) in BL, 63 % (5/8) in DLBCL, 63 % (5/8) in BL/DLBCL] and mean Ki-67 proliferation index [(93±4.4)% in BL, (83±14.3)% in DLBCL, (80±11.5)% in BL/DLBCL] were significantly different between BL and DLBCL and between BL and BL/DLBCL. The frequency of c-myc rearrangement [98 % (79/81) in BL,38 % (3/8) in DLBCL, 50 % (4/8) in BL/DLBCL] and an extra copy of bcl-6 [0 % in BL, 38 % (3/8) in DLBCL, 25 % (2/8) in BL/DLBCL] were also significantly different between BL and DLBCL and between BL and BL/DLBCL. Conclusion Diagnosis of the mature aggressive B cell lymphomas in pediatrics should be based on the comprehensive review and integration of morphologic, immunohistochemical and molecular genetic features. BL/DLBCL is more likely a subgroup of the DLBCL in pediatric population. The expression of CD10 and bcl-6 but not bcl-2, a high Ki-67 PI (＞90 %) and a c-myc rearrangement but not bcl-2 or bcl-6rearrangement are the features of BL. Regardless of the expression of CD10 and bcl-6, positive staining for bcl2, Ki-67 PI below 90 % and an extra copy of the bcl-6 favor a diagnosis of DLBCL or BL/DLBCL.