Diagnostics
PD-L1 Expression and Clinicopathologic Associations in Mediastinal Aggressive Large B-Cell Lymphomas: A Retrospective Single-Center Study
By Serhat Kaymaz, Selçuk Cin, Tuğrul Elverdi and 2 others.
Abstract
Background
Programmed death-ligand 1 (PD-L1) contributes to immune escape and is a therapeutically relevant target in aggressive B-cell lymphomas. However, its distribution and clinicopathologic significance across primary mediastinal aggressive large B-cell lymphomas remain incompletely defined.
Methods
We retrospectively reviewed 53 cases diagnosed between 2010 and 2025, including diffuse large B-cell lymphoma (DLBCL), primary mediastinal large B-cell lymphoma (PMBCL), mediastinal gray zone lymphoma (MGZL), and T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL). PD-L1 immunohistochemistry (clone 22C3) was performed on formalin-fixed, paraffin-embedded tissue. Tumor cells and intratumoral inflammatory cells were assessed together. Membranous staining was scored as 0, 1+, 2+, or 3+, and the proportion of cells in each category was recorded.