Identification of biological markers of sensitivity to high-clinical-risk-adapted therapy for patients with diffuse large B-cell lymphoma

Construction and validation of a risk scoring model for diffuse large B-cell lymphoma based on ferroptosis-related genes and its association with immune infiltration

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Categorization of DLBCL into four clusters based on survival- and ferroptosis-related factors.

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Establishment of an efficient risk scoring model is established for patients with DLBCL.

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Ferroptosis-based risk scoring model reveals immune infiltration correlation in DLBCL.

Backgrounds

The prognostic significance of ferroptosis-related genes is well known. However, survival- and ferroptosis-related genes are not currently considered in risk scoring models for diffuse large B-cell lymphoma (DLBCL).

Materials and methods

Ferroptosis regulators and markers were downloaded from the FerrDb database. The transcriptome profiling data were collected from the cancer genome atlas (TCGA). Transcriptome data and corresponding clinical information of DLBCL were downloaded from the gene expression omnibus (GEO). The validation data were downloaded using the UCSC Xena browser. ConsensusClusterPlus was used to categorize DLBCL samples according to gene expression profiles. The survival function was plotted with the Kaplan-Meier plots. The nomogram was built using multivariate logistic regression analysis and the Cox proportional hazards regression model.

Results

Based on the GSE11318 dataset of 203 samples and 267 ferroptosis-related gene expression profiles, we identified four clusters. A total of 19 survival-related genes were found associated with ferroptosis. The prognostic risk scoring model was constructed based on the regression coefficients. The obtained area under the receiver operating characteristic curve (AUC) values were 0.769, 0.801, and 0.791 for 1-, 3-, and 5-year survival, respectively. DLBCL samples with cluster 2 or cancer stage IV have shorter survival. Correlations between the immune infiltration and risk scores of the 12 immune cells were demonstrated. The response of DLBCL to doxorubicin was effectively validated by the risk scoring model.

Conclusions

In this study, a ferroptosis-based risk scoring model for patients with DLBCL was constructed and validated in an independent dataset. This risk score model has a better efficacy in predicting survival compared to clinical characteristics.

The PD-1/PD-L1 Checkpoint in Normal Germinal Centers and Diffuse Large B-Cell Lymphomas

Besides a recognized role of PD-1/PD-L1 checkpoint in anti-tumour immune evasion, there is accumulating evidence that PD-1/PD-L1 interactions between B and T cells also play an important role in normal germinal center (GC) reactions. Even when smaller in number, T follicular helper cells (TFH) and regulatory T (TFR) or B (Breg) cells are involved in positive selection of GC B cells and may result critical in the lymphoma microenvironment. Here, we discuss a role of PD-1/PD-L1 during tumour evolution in diffuse large B cell lymphoma (DLBCL), a paradigm of GC-derived lymphomagenesis. We depict a progression model, in two phases, where malignant B cells take advantage of positive selection signals derived from correct antigen-presentation and PD-1/PD-L1 inter-cellular crosstalks to survive and initiate tumour expansion. Later, a constant pressure for the accumulation of genetic/epigenetic alterations facilitates that DLBCL cells exhibit higher PD-L1 levels and capacity to secrete IL-10, resembling Breg-like features. As a result, a complex immunosuppressive microenvironment is established where DLBCL cells sustain proliferation and survival by impairing regulatory control of TFR cells and limiting IL-21-mediated anti-tumour functions of TFH cells and maximize the use of PD-1/PD-L1 signaling to escape from CD8+ cytotoxic activity. Integration of these molecular and cellular addictions into a framework may contribute to the better understanding of the lymphoma microenvironment and contribute to the rationale for novel PD-1/PD-L1-based combinational immunotherapies in DLBCL.

Infiltration of effector regulatory T cells predicts poor prognosis of diffuse large B-cell lymphoma, not otherwise specified

Regulatory T cells (Tregs) specifically express the transcription factor forkhead box P3 (FOXP3) and contribute to tumor progression. FOXP3-positive cells have been recently proven to be heterogeneous in phenotype and function, including effector Tregs (eTregs), naïve Tregs, and non-Tregs, which harbor no suppressive function. Therefore, it is crucial to investigate the "true Treg (eTreg)" population, rather than the entire FOXP3 population, with regards to their effect on tumor immunity. In particular, in diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), FOXP3-positive cells correlated with a better prognosis. The present study sought to evaluate the relationship between the prognosis of DLBCL, NOS patients and the infiltration of true Tregs by employing dual immunostaining with FOXP3 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4). CTLA-4 is a negative immunomodulatory known to be expressed by eTregs, but not by non-Tregs. Lymph nodes from 82 nodal DLBCL, NOS patients were stained with anti-FOXP3 and anti-CTLA-4 antibodies. A high infiltration of FOXP3-positive cells was associated with a significantly better prognosis than patients with low levels of FOXP3-positive cells for overall survival (OS) (P = .0233). In sharp contrast, a high infiltration of FOXP3/CTLA-4 double-positive cells was significantly associated with a poor prognosis than patients with low levels of FOXP3/CTLA-4 double-positive cells for OS (P = .0121) and progression-free survival (P = .0171), independent of the international prognostic index. FOXP3/CTLA-4 double-positive cells, eTregs, play an important role in DLBCL, NOS progression.

Peripheral blood regulatory T cell levels are correlated with some poor prognostic markers in newly diagnosed lymphoma patients

BACKGROUND

Regulatory T cells (Tregs) are a specialized subpopulation of CD4+ T cells which maintain the immune system homeostasis. They may increase during cancer progression and have been correlated with a worse prognosis in many malignancies. However, the role of Treg cells in lymphoma is debated.

METHODS

In this study, we assessed the peripheral blood levels of CD4+ CD25+ FOXP3+ Tregs in newly diagnosed patients with lymphoma and tried to find a relationship with patient characteristics. Twenty one patients with Hodgkin lymphoma (HL), 40 patients with non Hodgkin lymphoma (NHL) and 30 healthy sex matched controls were included in the study. Analysis were done by 3-color flow cytometry and only helper T cells were selected directly using CD4perCP as a gating strategy.

RESULTS

In HL group; there was a positive correlation with IPS, CRP, LDH and negative correlation with albumin, absolute lymphocyte count. Tregs were higher in male HL patients. In NHL group; there was a positive correlation with stage, IPI, CRP, LDH and a negative correlation with albumin ve absolute lymphocyte count.

CONCLUSIONS

There is a relationship between peripheral blood Treg levels and some poor prognostic parameters in newly diagnosed lymphoma patients. This relationship suggests a possible prognostic role of Tregs in lymphoma. Further research is needed in determining how to use Tregs as a prognostic factor. © 2015 International Clinical Cytometry Society.