# Is There an Immunohistochemical PD-L1 Cut-Off Point That Serves as a Prognostic Indicator for Large B-Cell Lymphomas?

## TL;DR

This study explores if PD-L1 expression levels can predict survival in large B-cell lymphoma patients, finding a potential 70% cut-off for prognosis.

## Contribution

The study identifies a potential 70% PD-L1 cut-off as a prognostic indicator in large B-cell lymphomas.

## Key findings

- A 70% PD-L1 cut-off showed a significant survival discrepancy in large B-cell lymphoma patients.
- ABC-like DLBCL-NOS cases exhibited higher PD-L1 expression compared to GCB-like cases.
- PD-L1 expression was a significant prognostic factor, especially in the ABC-like phenotype.

## Abstract

The aim of this study is to investigate whether there is a cut-off value for PD-L1 expression in large B-cell lymphomas that predicts prognosis, and to clarify the relationship between PD-L1 expression and histopathological as well as clinical parameters. The study included a total of 130 patients who were diagnosed with large B-cell lymphoma at Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Pathology Department. Biopsy samples were assessed using the PD-L1 immunohistochemical antibody (Dako, 22C3 clone). The patients had a mean age of 54 ± 17 years, with a median age of 56 years. No statistically significant difference was observed between the groups in terms of survival when the 30% cut-off value was used. However, a noteworthy discrepancy in survival became apparent when the cut-off point was established at 70%. Among the diffuse large B-cell lymphoma-not otherwise specified (DLBCL-NOS) category, the activated B-cell-like (ABC-like) phenotype showed higher PD-L1 expression compared to the germinal center B-cell-like (GCB-like) phenotype. Immunohistochemical PD-L1 expression emerged as a prognostic factor, particularly significant in the ABC-like phenotype.