Immunohistochemical overexpression of BCL-2 protein predicts an inferior survival in patients with primary central nervous system diffuse large B-cell lymphoma

Sinonasal DLBCL: molecular profiling identifies subtypes with distinctive prognosis and targetable genetic features

ABSTRACT

Primary sinonasal diffuse large B-cell lymphoma (PSDLBCL) is a rare lymphoma with a variable prognosis and a unique relapse/dissemination pattern involving the central nervous system and skin. The underlying molecular mechanisms leading to this heterogeneity and progression pattern remain uncharted, hampering patient-tailored treatment. To investigate associated mechanisms, we analyzed clinical data and used immunohistochemistry, gene-expression profiling, cytogenetics, and next-generation sequencing in a cohort of 117 patients with PSDLBCL. The distribution in cell-of-origin (COO) was 68 (58%) activated B-cell (ABC), 44 (38%) germinal center B-cell (GCB), and 5 (4%) unclassifiable. COO was significantly associated with progression-free survival (PFS) and lymphoma-specific mortality (LSM) in both the overall cohort (5-year PFS: ABC, 43% vs GCB, 73%; LSM: ABC, 45% vs GCB, 14%) and in the subgroup of patients receiving immunochemotherapy (5-year PFS: ABC, 55% vs GCB, 85%; LSM: ABC, 28% vs GCB, 0%). ABC lymphomas were mainly MCD class, showing a high prevalence of MYD88 (74%) and CD79B (35%) mutations compared with GCB lymphomas (MYD88 23%; CD79B 10%) (P < .01). The ABC subtype frequently displayed cMYC/BCL2 coexpression (76% vs 18% GCB; P < .001) and HLA-II loss (48% vs 10% GCB; P < .001). PD-L1 expression and copy-number alterations were rare. All lymphomas were Epstein-Barr virus-negative. Our data suggest molecular profiling as a potent tool for detecting prognostic subgroups in PSDLBCL, exposing links to known relapse/dissemination sites. The ABC subgroup's MCD genetic features, shared with lymphomas at other nonprofessional lymphoid sites, make them potential candidates for targeted B-cell and toll-like receptor signaling therapy.

Knockdown of the long non‑coding RNA CACNA1G‑AS1 enhances cytotoxicity and apoptosis of human diffuse large B cell lymphoma by regulating miR‑3160‑5p

Abstract: Long non-coding RNAs (lncRNAs) have been confirmed to be connected with tumor proliferation, apoptosis, metastasis and recurrence. Previous studies have indicated that lncRNA calcium voltage-gated channel subunit α1 G (CACNA1G)-antisense 1 (AS1) can function as a pro-oncogene in several types of cancer. However, the specific role and mechanism of CACNA1G-AS1 have not been fully elucidated in human diffuse large B cell lymphoma (DLBCL). In the present study, CACNA1G-AS1 expression was verified in DLBCL tissues and cells by reverse transcription-quantitative PCR, and the relationship between CACNA1G-AS1 and microRNA (miR)-3160-5p was confirmed using luciferase reporter assays. After CACNA1G-AS1-knockdown and miR-3160-5p-overexpression, MTT, colony formation and flow cytometry assays were conducted to assess the changes in the cytotoxicity and apoptosis of OCI-Ly10 and SUDHL-4 cells. In addition, in vivo experiments were performed to determine the impact of CACNA1G-AS1-knockdown on tumor growth and apoptosis. It was revealed that CACNA1G-AS1 was highly expressed in DLBCL tissues and cells and that expression of CACNA1G-AS1 was associated with the clinical stage of DLBCL. Functionally, CACNA1G-AS1-knockdown was demonstrated to increase cytotoxicity and expedite apoptosis in DLBCL cells in vitro and in vivo. In addition, CACNA1G-AS1 could downregulate miR-3160-5p by targeting binding in DLBCL cells. Overexpression of miR-3160-5p had the same effects on the cytotoxicity and apoptosis of DLBCL cells as CACNA1G-AS1-knockdown. Overall, the present study revealed that CACNA1G-AS1-knockdown and miR-3160-5p-overexpression could prevent DLBCL carcinogenesis, which might provide novel therapeutic targets for DLBCL.

A genetically distinct pediatric subtype of primary CNS large B-cell lymphoma is associated with favorable clinical outcome

Primary central nervous system large B-cell lymphoma (PCNS-LBCL) occurs typically in older adults and only rarely in the pediatric population. The genomic landscape of PCNS-LBCL in children and young adults (YA) is not well-characterized. In this multi-institutional study, targeted next-generation DNA sequencing and chromosomal copy number analysis was performed on a cohort of 12 pediatric and YA (age<40 years) PCNS-LBCL patients without known immunodeficiency and correlated with clinicopathologic data. Based on genomic features, we identified two subgroups: a unique "Pediatric type, MYD88-wildtype" group (median age 14 years, range 7-25 years) was characterized by absence of MYD88 mutations but frequent genetic alterations in TP53 (6/8, 75%), NFKBIE (4/8, 50%), and GNA13 (4/8, 50%); and an "adult type, MYD88-mutant" group (median age 35 years, range 25-38 years) was defined by MYD88 hotspot mutations (4/4, 100%), with frequent PRDM1 mutation/deletion (3/4, 75%), CDKN2A/B homozygous deletion (3/4, 75%), and deletions of the HLA gene cluster (2/4, 50%). Kaplan-Meier analysis demonstrated that patients with pediatric type, MYD88-wildtype PCNS-LBCL had favorable outcomes (median survival: >100 months; 5-year-overall survival: 100%). In conclusion, we have identified a new pediatric type of PCNS-LBCL that is molecularly distinct from PCNS-LBCL occurring in adults, based on an absence of MYD88 mutation, CDKN2A/B homozygous deletion, deletion of HLA gene cluster, and paucity of CD79B and PRDM1 mutations, along with an enrichment for TP53, NFKBIE, and GNA13 mutations. Patients with pediatric type, MYD88-wildtype PCNS-LBCL often have long-term survival compared to their adult counterparts.

Clinical Features and Prognostic Significance of NOTCH1 Mutations in Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of large lymphoid B cell malignancy with distinct clinical and genetic features. Recently, NOTCH1 mutations were identified in DLBCL cases by Next-generation sequencing (NGS), but the clinical features and prognostic impact were not systematically studied. Here, NOTCH1 genes in 161 DLBCL samples were sequenced by NGS. The prognostic value of NOTCH1 mutations was assessed in the context of clinical and laboratory factors, such as international prognostic index (IPI), cell-of-origin classification, double expression of BCL2 and c-MYC. The combined data from three Western cohorts were used to validate these results. As a result, NOTCH1 mutations were found in 17(10.6%) patients, and three patients had a hotspot mutation of c.7541_7542delCT. The presence of NOTCH1 mutations was significantly associated with poor complete response and progression free survival(PFS), which was independent of established clinical and laboratory parameters. In addition, 30 (1.92%) of 1562 patients treated with R-CHOP regimen in those combined Western cohorts had NOTCH1 mutations. Meta-analysis of the Western cohorts confirmed that NOTCH1 mutations were also associated with poor PFS and OS. In conclusion, DLBCL patients with the NOTCH1 mutations have worse PFS and OS, and the NOTCH1 mutations can be used as an independent predictor for patients with DLBCL.

[Research of prognostic immunophenotypes in 163 patients of diffuse large B-cell lymphoma]

Objective: To screen and analyze the prognostic protein biomarkers of DLBCL, and to explore their value in the prognostic evaluation. Methods: 163 cases of confirmed DLBCLs from January 2011 to December 2016 were collected with their clinical, pathological and follow-up data, which were all from our hospital. The expression of protein markers were tested using immunohistochemical staining (IHC) . The immune phenotypes independent of the International Prognostic Index (IPI) that affect overall survival (OS) and progression-free survival (PFS) of DLBCL were explored by COX regression model, and the effect of their co-expression on the prognosis were also analyzed. Result: BCL6 negative (PFS: HR=1.652, 95%CI 1.030-2.649, P=0.037) , P53 positive (OS: HR=1.842, 95%CI 1.008-3.367, P=0.047) , and BCL2 strong positive expressions (S+) (OS: HR=2.102, 95%CI 1.249-3.537, P=0.005; PFS: HR=2.126, 95%CI 1.312-3.443, P=0.002) are adverse prognostic factors of DLBCL that are independent of IPI. BCL6(-) (PFS: HR=2.042, 95%CI 1.021-4.081, P=0.043) , P53(+) (OS: HR=3.069, 95%CI 1.244-7.569, P=0.015) and BCL2(S+) (OS: HR=2.433, 95%CI 1.165-5.082, P=0.018; PFS: HR=3.209, 95%CI 1.606-6.410, P=0.001) are adverse prognostic factors in the group of age≤60-year-old; in the group of IPI score 0-2, cases with BCL6(-) (OS: HR=2.467, 95%CI 1.322-4.604, P=0.005; PFS: HR=2.248, 95%CI 1.275-3.965, P=0.005) and BCL2(S+) (PFS: HR=2.045, 95%CI 1.119-3.735, P=0.020) have worse prognosis. The co-expression of BCL6(-) and BCL2(S+) has significant influence on prognosis of DLBCL (P=0.005 and P<0.001) , in which BCL6(+)/non-BCL2(S+) (n=86) has the best prognosis[3-year-OS (71.6±4.9) %, 3-year-PFS (67.0±5.1) %], and BCL6(-)/BCL2(S+) (n=10) has the worst prognosis[3-year-OS (20.0±12.6) %, 3-year-PFS (10.0±9.5) %]; the co-expression of BCL6(-) and P53(+) has no significant influence on prognosis (P=0.061 and P=0.089) , however, those cases with BCL6(+)/P53(-) (n=98) often get better prognosis[3-year-OS (70.6±4.7) %, 3-year-PFS (64.6±4.9) %] than others; the co-expression of P53(+) and BCL2(S+) has significant influence on prognosis of DLBCL (P<0.001 and P<0.001) , and P53(+)/BCL2(S+) (n=5) has the worst prognosis (3-year-OS and 3-year-PFS are both 0) ; BCL2(S+) cases get shorter OS and PFS, regardless of the expression of BCL6 and P53. Conclusion: The expression and co-expression of BCL6 negative, P53 positive and BCL2(S+) have certain value in the prognostic evaluation of DLBCL, especially in the group of age≤60-year-old and IPI score 0-2.