Histological analysis of spleens and lymph nodes in WT mice and representative malignancies in miR-146a or miR-146b KO mice. (A) Increased rate of tumorigenesis in mice with miR-146a or miR-146b ablation. n = 11 (WT), 8 (miR-146a KO1), 3 (miR-146a KO2), and 21 (miR-146b KO). (B) Photograph of spleens isolated from WT and miR-146b KO mice at 16 months. (C) miR-146a and miR-146b KO mice developed B-cell lymphomas in the spleen and lymph nodes. Scale bars represent 500 µm (low magnification), 20 µm (high magnification), and 2.5 µm (insets). (D) miR-146b KO mice developed acute leukemia. Scale bars represent 500 µm (low magnification) and 20 µm (high magnification), and 2.5 µm (inset). HE, hematoxylin and eosin; FL, follicular lymphoma.