The number of tumor-infiltrating lymphocytes is functionally important and correlates with clinical outcome in several tumor entities. Herein we explore the impact of the density of T and B lymphocytes in prostate cancer tissue on prostate-specific antigen (PSA) recurrence after prostatectomy in 3261 prostate cancer tissue samples. The number of prostate cancer-infiltrating CD3-positive T cells and CD20-positive B cells per tissue spot in a tissue microarray format was determined by immunohistochemistry and was correlated with clinical and pathological data from the same patient cohort. Patients with very low and very high numbers of CD3-positive T cells per tissue spot had a significantly shorter PSA recurrence-free survival compared to patients with intermediate numbers of T cells (p = 0.0188). Furthermore, a high number of CD3-positive T cells per tissue spot was associated with fusion type prostate cancer identified by ERG expression analysis. The number of CD20-positive B cells per tissue spot was not associated with other clinical and histopathological parameters. This study indicates that the density of T but not B cells plays a functional role in the biology of prostate cancer and may have an impact on clinical outcome in this frequent neoplasia.
