Prognostic value of chromosomal translocations in small-bowel diffuse large B-cell lymphoma

Colorectal diffuse large B-cell lymphoma: molecular subclassification and prognostic significance of immunoglobulin gene translocation

Primary colorectal diffuse large B-cell lymphoma (DLBCL) is rare, and its clinicopathological and genetic features are poorly understood. The aim of our study was to elucidate the frequency and prognostic significance of molecular subgroups in colorectal DLBCL. We examined 25 cases of colorectal lymphoma with DLBCL-like morphology and classified them into germinal center B-cell like (GCB)/non-GCB subgroups by immunohistochemistry (IHC) for CD10, bcl-6 and MUM1, or into double-expressor (DE)/non-DE subgroups by IHC for bcl-2 and c-myc. Translocations involving BCL2, BCL6, MYC, IGH, IGK, IGL, and MALT1 were also investigated using break-apart fluorescence in situ hybridization (FISH). The 25 cases were classified into two entities-DLBCL, not otherwise specified (NOS) (n = 23; 92%) and high grade B-cell lymphoma, double hit (n = 2; 8%)-according to the recent WHO classification. None of them showed histological evidence of Epstein-Barr virus infection or high-grade transformation from low grade B-cell lymphoma. Ten cases were GCB-type and four cases were DE-type, but these subtypes did not contribute to clinicopathological differences. Translocations involving BCL2, BCL6, MYC, IGH, IGK, IGL, and MALT1 were detected in 3 (12%), 3 (12%), 10 (40%), 14 (56%), 3 (12%), 3 (12%), and 0 (0%) of 25 cases, respectively. Of note, the presence of IGH translocation was significantly associated with better overall survival (P = .0053) and progression free survival (P = .0259). Similarly, the translocation involving at least one of the IGs (IGH, IGK, and/or IGL) was associated with more favorable prognosis in DLBCLs or even in DLBCL, NOS. This is the first report to reveal that a small subset of colorectal DLBCL corresponds to double-hit lymphoma. In addition, translocations involving at least one of the IGs may be a favorable prognostic factor in colorectal DLBCL. Testing the translocation involving rearrangement of IGs as well as MYC and BCL2/BCL6 may thus be useful for diagnosis and prognosis.

Clinicopathological analysis of primary intestinal diffuse large B-cell lymphoma: Prognostic evaluation of CD5, PD-L1, and Epstein-Barr virus on tumor cells

BACKGROUND

Primary intestinal diffuse large B-cell lymphoma (iDLBCL) is rare. In this study, we investigated the clinicopathological features of this disease to further understand the prognostic value of CD5, programmed cell death ligand 1 (PD-L1), and Epstein-Barr virus (EBV) on tumor cells.

METHODS

Tumor specimens from 62 patients consecutively diagnosed with primary iDLBCL at a single institution were analyzed.

RESULTS

Our series consisted of EBV-positive (EBV⁺ ) iDLBCL (n = 10), de novo CD5⁺ iDLBCL (n = 4), and DLBCL, not otherwise specified (DLBCL-NOS; n = 48). Notably, seven of 10 EBV⁺ cases had treated lymphoma-associated (n = 4) or iatrogenic immunodeficiency (n = 3). Two of 10 EBV⁺ cases expressed PD-L1 on tumor cells, whereas the remaining eight were positive for PD-L1 on microenvironment immune cells. Only one DLBCL-NOS case had neoplastic PD-L1 expression with a giant cell-rich appearance. Both EBV-harboring and PD-L1 expression on tumor cells, but not CD5, were associated with worse overall survival (OS) in iDLBCL patients receiving rituximab-containing chemotherapy (P = 0.0354, P = 0.0092, and P = 0.1097, respectively). Multivariate analysis identified PD-L1 positivity on tumor cells (P = 0.0106), PD-L1 negativity on microenvironment immune cells (P = 0.0193), and EBV positivity (P = 0.0324) as poor independent prognostic factors for OS. Among iDLBCL cases without any EBV association, CD5 positivity, or neoplastic PD-L1 expression, high PD-L1 expression (≥40%) on microenvironment immune cells predicted an extremely favorable outcome.

CONCLUSION

EBV⁺ iDLBCL mainly comprised immunodeficiency-associated patients, which may highlight the specificity of the intestine. PD-L1 expression on tumor cells or microenvironment immune cells was found to have an opposite prognostic impact in iDLBCL.