MYC and urinary bladder neoplasm: Both a nuclear and a cytoplasmic distribution of Myc was observed; however, the number of Myc-positive nuclei in the mouse urothelium treated with BBN and nicotinamide was significantly lower than in the BBN-induced bladder tumor, and the cytoplasmic staining intensity of Myc in either BBN group was weaker than that in normal urothelium (Figure 4, C and Table 1).