Clinicopathologic and molecular genetics features of mature aggressive B-cell lymphomas in pediatrics / 白血病·淋巴瘤

ABSTRACT

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.