Objective: Primary central nervous system lymphoma (PCNSL) is a rare and aggressive extranodal variant of non-Hodgkin lymphomas with disease confined to the brain, spinal cord, leptomeninges, or orbit, without evidence of systemic involvement. PCNSL has a poor prognosis, with a median overall survival of 30–50 months. We used NanoString Technologies to characterize the cancer immune profiles in PCNSL and associated the findings with clinical outcome.
Materials and Methods: A total of 33 patients between 2005 and 2017 were included in our study, and clinical information was collected. A PanCancer IO 360 panel (NanoString Technologies) was used to assess the expression level of 770 genes related to tumor immunity in 12 samples. We also investigated the programmed death ligand 1 (PD-L1) expression and T-cell infiltrate in 25 PCNSL samples using immunohistochemistry.
Results: NanoString analysis showed that gene expressions differed between human immunodeficiency virus (HIV)-positive and HIV-negative PCNSL. We identified four genes with deregulated expressions (adjusted p<0.05) with a cluster enrichment in cytotoxicity, DNA damage repair, interferon signaling, and lymphoid compartment-related genes. Furthermore, we found that PD-L1 was expressed in 9 of 25 (36%) cases and 11 had increased CD3+ T-cell infiltrates. However, increased PD-L1 expression and CD3+ T-cell infiltrates were not correlated with the clinical outcome.
Conclusion: Our data reveals a distinct PCNSL tumor microenvironment and immune landscape. However, our study needs to be validated in a larger population.