Development of plasma cell tumors in p80HT mice. (A) A summary of histological examination of tumor samples (lymph nodes) from p80HT mice. (B) Hematoxylin and Eosin (H&E) and CD138 immunohistochemistry staining (CD138-IHC) of the lymph node from a wild-type (WT) mouse and a representative tumor sample from the p80HT mouse #491. The tumor sample shows nodules of plasma cells expressing CD138. (C) CD138 immunohistochemistry staining showing accumulation of plasma cells in both the tumor (LN) and bone marrow (BM) samples from the p80HT mouse #379. Scale bars, 50 μm.