Burkitt lymphoma is immunophenotypically different from Burkitt-like lymphoma in young persons

Introduction. Burkitt-like lymphoma (BLL) is a provisional category of B-ce ll lymphoma which is morphologically intermediate between Burkitt lymphoma (BL) and large B-cell lymphoma (LBCL). The clinical significance of this mo rphology is controversial. Patients and methods: We examined 41 cases of pediatric B-cell lymphoma by immunohistochemistry For proteins associated with proto-oncogenes c-myc, BC L-2 and BCL-6 and a subset of cases (with adequate slides) for a proliferat ion-associated marker (Ki-67) and for apoptosis (Apop-Tag). Sixteen cases o f BLL, thirteen cases of BL and twelve cases of LBCL were examined. Results. Our results showed BCL-6 expression in 16 of 16 BLL, 4 of 13 BL, a nd 9 of 12 LBCL; c-myc expression in 14 of 15 BLL, 9 of 13 BL, and 12 of 12 LBCL; and BCL-2 expression in 2 of 16 BLL, 0 of 13 BL and 6 of 12 LBCL. Me an apoptotic index for BLL was 10.3% (n = 6); for BL was 17.1% (n = 5); and for LBCL was 10.9% (n = 6), Ki-67 was diffusely reactive in all cases test ed. There was a significantly higher proportion of BLL than BL which expres sed BCL-6 (P = 0.0001). Conclusions: Labeling for BCL-6 distinguishes BLL from BL. It is likely tha t in children in North America, BLL is biologically distinct from BL and mo re closely resembles a subset of LBCL.