Figure 2: Microscopic histomorphology (H&E staining 100). The bladders from Control (a) and -3-treated-rats (b) had no signs of preneoplastic or neoplasic lesions. In the BBN group (c1 and c2), all the bladders presented preneoplastic lesions, namely, hyperplasia and high-grade dysplasia (c1), even in the bladders without tumor growth. Neoplasic lesions like papillary tumors (c2), infiltrative tumors, and Cis were found in some bladders of the BBN-treated-rats. In the -3 + BBN rats, all the bladders also presented hyperplasia (d1), but high-grade dysplasia was absent, and the tumors were of papillary nature (d2), but no infiltrative tumors and Cis were found.