Prognostic effect of stromal lymphocyte infiltration in thrymic carcinoma

BackgroundThe purpose of this study was to clarify the relationship between the tumor infiltrating lymphocytes and clinical outcome in patients with thymic carcinoma.MethodsTissue specimens from 32 patients who underwent surgical resection for thymic carcinoma were immunohistochemically analyzed for CD4, CD8 and CD20 expression.ResultsTumor-infiltrating lymphocytes were generally more abundant in the stroma. The patients with low CD4+ lymphocytes (p = 0.037) and low CD20+ lymphocytes (p = 0.045) within tumor stroma showed poor survival. Furthermore, concurrent low levels of CD4+ and CD20+ (p = 0.014), CD8+ and CD20+ (p = 0.025), and, CD4+, CD8+, and CD20+ (p = 0.025) in tumor stroma were significantly associated with poor prognosis when compared to the others group.ConclusionOur results indicate that infiltrating CD4+, CD8+, and CD20+ lymphocytes in cancer stroma may cooperate to suppress cancer progression and their presence together appear to be prognostic factor in thymic carcinoma.