“…Number of animals examined for immunohistochemical analysis including normal thymuses, hyperplastic lesions, and thymomas are shown in Table1. The paraffin sections were analyzed immunohistochemically using antibodies against CK18 (Ks18.04, Mouse monoclonal, PROGEN Biotechnik, GmbH, Heidelberg, Germany) for cortical epithelium, 7 CK14 (EPR17350, Rabbit monoclonal; Abcam, Cambridge, MA, USA) for medullary epithelium, 9 and CD20 (M-20, Goat polyclonal; Santa Cruz Biotechnology, Inc., Santa Cruz, CA, USA) for B lymphocytes. Secondary antibody used the polymer kit (HISTOFINE Simple Stain Mouse MAX-PO; Nichirei Bioscience, Inc., Tokyo, Japan).…”