Several studies have suggested that B cells play a role in controlling cancer.10–12 In a study of 1470 primary invasive breast carcinomas, higher total number of infiltrating CD20+ B cells was associated with significantly longer disease-free intervals.20 This benefit was independent of tumor grade, tumor size, cancer cell invasion status of the lymph nodes, and CD8+ T cell counts.20 Extending beyond the tumor, our data demonstrate that higher B cell numbers in SLNs are also associated with longer DFS. The gene discussed is CD8A; the disease is invasive breast carcinoma.