PAX5 and diffuse large B-cell lymphoma: Immunohistochemical analyses of the spleen and lymph nodes (LNs) from BU-322 and BU-434 mice revealed loss of the normal architecture with follicular and diffuse expansion of neoplastic B220+Pax5+ B-lymphocytes, showing FL- and diffuse large B cell lymphoma (DLBCL)-like appearance, respectively (Fig. 2B left panel).