miR expression in MYC-negative DLBCL/BL with partial trisomy 11 is similar to classical Burkitt lymphoma and different from diffuse large B-cell lymphoma.

Fast and reliable differential diagnosis of Burkitt lymphoma (BL) vs. diffuse large B cell lymphoma (DLBCL) is of major importance for therapeutic decisions and patient outcome. Aggressive B cell non-Hodgkin lymphomas (B-NHLs) that do not belong to the abovementioned entities were categorized by the current WHO lymphoma classification as "B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL" (DLBCL/BL). We have recently described a DLBCL/BL subgroup with recurrent chromosome 11q aberrations, resembling BL (B-NHLs[11q]). Here, we analyzed 102 prospectively collected fine needle aspirates from patients with aggressive B-NHLs in order to investigate the potential of microRNA (miR)-155, its precursor BIC, as well as miR-21 and miR-26a to differentiate BL from DLBCL, and from DLBCL/BL that include B-NHLs[11q]. Both BL and DLBCL/BL cases, including B-NHLs[11q], demonstrated significantly lower expression levels of miR-155/BIC, miR-21, and miR-26a compared to primary DLBCL. In conclusion, the miRs expression in B-NHLs[11q] provides a new suggestion, in addition to pathomorphological and clinical similarities between classical, i.e., MYC translocation-positive BL, and B-NHLs[11q], to recognize the B-NHLs[11q] subgroup of DLBCL/BL category as a MYC translocation-negative variant of BL in most cases, and points to the potential utility of miR-155/BIC/miR-21/miR-26a for the differential diagnosis of a heterogeneous category of DLBCL/BL.