Low Density of CD3+ Tumor-Infiltrating Lymphocytes Is Predictive of a Poor Prognosis in Diffuse Large B-Cell Lymphoma Independently of MYC and BCL2 Double Expression Status: A Potential Utility of Immunoscore Based on Whole-Slide Image Analysis

Background: Anti-tumor immunity plays a key role in tumor development and progression and the landscape of tumor immune microenvironment could affect the clinical outcome of patients. The concept of immunoscore based on immune cell infiltration has been actively applied to solid tumors including colon cancer and malignant melanoma and successfully predicted prognosis of patients. However, a potential utility of immunoscore in predicting prognosis of patients with diffuse large B-cell lymphoma (DLBCL) remains unclear. For easy application of immunoscore to daily practice, we investigated the prognostic value of tumor-infiltrating CD3+ T-cell density which is routinely stained for diagnosing malignant lymphomas, and then explored the feasibility of immunoscore application in DLBCL.