High hyperdiploid karyotype with ≥ 49 chromosomes represents a heterogeneous subgroup of acute myeloid leukemia with differential TP53 mutation status and prognosis: a single-center study from China.

High hyperdiploid karyotype with ≥ 49 chromosomes (which will be referred to as HHK) is rare in acute myeloid leukemia (AML). The European leukemia network (ELN) excluded those harboring only numerical changes (with ≥ 3 chromosome gains) from CK and listed them in the intermediate risk group, while the UK National Cancer Research Institute Adult Leukaemia Working Group classification defined ≥ 4 unrelated chromosome abnormalities as the cutoff for a poorer prognosis. Controversies occurred among studies on the clinical outcome of HHK AML, and their molecular characteristics remained unstudied. We identified 1.31% (133/10,131) HHK cases within our center, among which 48 cases only had numerical changes (NUM), 42 had ELN defined adverse abnormalities (ADV) and 43 had other structural abnormalities (STR). Our study demonstrated that: (1) No statistical significance for overall survival (OS) was observed among three cytogenetic subgroups (NUM, STR and ADV) and HHK AML should be assigned to the adverse cytogenetic risk group. (2) The OS was significantly worse in HHK AML with ≥ 51 chromosomes compared with those with 49-50 chromosomes. (3) The clinical characteristics were similar between NUM and STR group compared to ADV group. The former two groups had higher white blood cell counts and blasts, lower platelet counts, and mutations associated with signaling, while the ADV group exhibited older age, higher chromosome counts, higher percentage of myelodysplastic syndrome (MDS) history, and a dominant TP53 mutation.

Prognostic significance of histologic grade and Ki-67 proliferation index in follicular lymphoma.

The prognostic value of histologic grading and the Ki-67 proliferation index in follicular lymphoma (FL) is controversial. This study investigated the clinical usefulness of these two factors in Asian FL patients. Four hundred and thirty-three patients diagnosed with FL were retrospectively reviewed with a median follow-up time of 47.0 months (range, 24.0-168.0). The 10-year overall survival (OS) rate and progression-free survival (PFS) rate were 91.0% and 47.1%, respectively. Grade 3B and grade 3B with diffuse large B cell lymphoma (DLBCL) showed a better PFS than grade 1-3A (P < 0.001), and similar findings were noted in patients who received rituximab-containing regimens (P = 0.002). In contrast, no significant differences in terms of OS or PFS were observed between grades 1-2 and 3A. In addition, patients with Ki-67 ≥ 30% had a significantly better PFS than patients with Ki-67 < 30% (P = 0.014), although the difference was eliminated in the multivariate analysis. Both grade and Ki-67 index had no impact on prognosis in patients who did not receive rituximab treatment. In conclusion, grade 3A is closely related to grade 1-2, as reflected by a similar indolent clinical course and a lower PFS rate than grade 3B/3B + DLBCL. In addition, a higher Ki-67 index seems to have a positive effect on PFS in FL patients.

Cell-of-Origin Subtyping of Diffuse Large B-Cell Lymphoma by Using a qPCR-based Gene Expression Assay on Formalin-Fixed Paraffin-Embedded Tissues.

The well-established cell-of-origin (COO) algorithm categorizes diffuse large B-cell lymphoma (DLBCL) into activated B-cell-like (ABC) and germinal center B-cell-like (GCB) subgroups through gene expression profiling. We aimed to develop and validate a qPCR-based gene expression assay to determine the COO subgroups of DLBCL with formalin-fixed paraffin-embedded (FFPE) tissue. We first established a DLBCL transcriptome database of 1,016 samples retrieved from three published datasets (GSE10846, GSE22470, and GSE31312). With this database, we identified a qPCR-based 32-gene expression signature (DLBCL-COO assay) that is significantly associated with the COO subgroups. The DLBCL-COO assay was further validated in a cohort of 160 Chinese DLBCL patients. Biopsy samples from DLBCL patients with paired FFPE and fresh frozen tissue were collected to assign COO subtypes based on the immunohistochemistry (IHC) algorithm (Han's algorithm), DLBCL-COO assay, and global gene expression profiling with RNA-seq. For 111 paired FFPE and fresh DLBCL samples, the concordance between the IHC, qPCR, and RNA-seq methods was 77.5% and 91.9%, respectively. The DLBCL-COO assay demonstrated a significantly superior concordance of COO determination with the "gold standard" RNA-seq compared with the IHC assignment with Han's algorithm (P = 0.005). Furthermore, the overall survival of GCB patients defined by the DLBCL-COO assay was significantly superior to that of ABC patients (P = 0.023). This effect was not seen when the tumors were classified by the IHC algorithm. The DLBCL-COO assay provides flexibility and accuracy in DLBCL subtype characterization. These findings demonstrated that the DLBCL-COO assay might serve as a useful tool for guiding prognostic and therapeutic options for DLBCL patients.

Epstein-Barr virus-positive diffuse large B-cell lymphoma features disrupted antigen capture/presentation and hijacked T-cell suppression.

Background: B cells can function as antigen-presenting cells by presenting antigens captured by the B-cell receptor (BCR) on Class II Major Histocompatibility Complex (MHC II) to T cells. In addition, B-cells can also maintain immune homeostasis by expressing PD-L1 and suppressing T-cell activity. Epstein-Barr virus (EBV) infection can disrupt B-cell function and lead to B cell malignancies, including diffuse large B-cell lymphoma (DLBCL). Here we show that EBV-positive DLBCL (EBV+ DLBCL) has decreased expression of BCR and MHC II, but over-expressed PD-L1, which may lead to immune evasion. Methods: An EBV+ DLBCL cohort (n = 30) and an EBV- DLBCL control cohort (n = 83) were established. Immunostaining of PD-L1, MHC II, MHC II Transactivator (CIITA) and pBTK was performed on automated stainer. H-score was used to denote the results of staining of PD-L1 and pBTK. Break apart and deletion of CIITA locus was studied by fluorescent in situ hybridization. Surface immunoglobulin mean fluorescent insensitivity (MFI) was detected by flow cytometry to demonstrate the level BCR. Results: EBV+ DLBCL showed significantly lower expression of CIITA and MHC II compared to EBV- DLBCL. Genetic aberrations involving CIITA were also more common in EBV+ DLBCL, with 23% break apart events and 6% deletion events, comparted to 2% break apart and 0% deletion in EBV- DLBCL. In addition to the loss of antigen presentation molecule, the antigen capture receptor, BCR, was also down-regulated in EBV+ DLBCL. Accordingly, BCR signaling was also significantly decreased in EBV+ DLBCL as denoted by the respective pBTK levels. Conclusions: EBV+ DLBCL shows over expression of the T-cell inhibitory ligand, PD-L1. Antigen capture and presentation system were disrupted, and T-cell inhibitory molecule was hijacked in EBV+ DLBCL, which may contribute to immune escape in this high risk disease. Therapies targeting these aberrations may improve the outcome of patients with EBV+ DLBCL.