They found that BLL-11q has a genomic and mutational profile more closely related to that of high grade B-cell lymphoma (HGBCL) or diffuse large B-cell lymphoma (DLBCL) than typical Burkitt lymphoma (BL).
The researchers also found that BLL-11q has clinical, morphologic, and phenotypic features that are “more consistent” with HGBCL or DLBCL than with typical BL.
“These observations support a reconsideration of the ‘Burkitt-like’ term for these tumors,” Blanca Gonzalez-Farre, MD, of Hospital Clínic de Barcelona, and her colleagues wrote in Haematologica.
To reach this conclusion, the researchers performed copy number analysis and sequencing of B-cell lymphoma-related genes in 11 cases of BLL-11q.
The copy number analysis revealed that seven BLL-11q cases had the typical 11q gain/loss pattern, two had an 11q terminal deletion, one had two gains and two losses, and one had an 11q23.3-q25 copy number neutral loss of heterozygosity in addition to gain.
The BLL-11q cases also had frequent gains of 5q21.3-q32 and losses of 6q12.1-q21. However, they lacked the 1q gains observed in MYC-positive BL and alterations typically observed in germinal center B-cell like (GCB) DLBCL, such as gains in 2p16.1 and 7p.
Targeted sequencing of the BLL-11q cases revealed mutations typically observed in germinal center-derived lymphomas, including mutations in BTG2, DDX3X, ETS1, EP300, GNA13, CREBBP, KMT2C, EZH2, ARID1A, KMT2D, HIST1H1D, HIST1H2BC, and TMEM30A.
However, the BLL-11q cases lacked mutations in ID3, TCF3, and CCND3, which are typically observed in BL.
“In addition to the genetic differences, our BLL-11q differed clinically, morphologically, and phenotypically from conventional BL and instead showed features more consistent with HGBCL or DLBCL,” the researchers wrote.
Specifically, the BLL-11q patients were all younger than 40 years, with a median age of 15. Most presented with localized lymphadenopathy. And all had favorable treatment outcomes, remaining alive and free of disease at a median follow-up of 30 months.
All cases had a germinal center phenotype. They did not have the typical cytological features of BL, but they did have a high proliferative index, and some cases had a starry sky pattern.
The researchers said the BLL-11q cases were better classified as HGBCL not otherwise specified (n = 8), DLBCL (n = 2), and atypical BL (n = 1).
Considering these findings together, the team concluded that a more appropriate name for BLL-11q might be “aggressive B-cell lymphoma with 11q aberration.”
This research was supported by Asociación Española Contra el Cáncer and other organizations, as well as the government of Catalonia.
SOURCE: Gonzalez-Farre B et al. Haematologica. 2019 Feb 7. doi: 10.3324/haematol.2018.207928.