To establish an animal model mimicking invasive UC that arises from papillary non-invasive UC in the bladder, male human c-Ha-ras proto-oncogene transgenic rats (Hras128) were treated with 0.05% N-butyl-N-(hydroxybutyl)nitrosameine (BBN) in their drinking water and/or 0.1% phenylethyl isothiocyanate (PEITC) in their diet as follows: BBN (8 weeks)→PEITC (8 weeks); PEITC (8 weeks)→BBN (8 weeks); BBN alone (16 weeks); PEITC alone (16 weeks); and no treatment.
Since 5-10% of transitional cell carcinomas (TCCs) have been shown to contain a mutated HRAS gene, and protein expression levels of all forms of HRAS have been correlated with TCC progression, we chose to study the contribution of the HRAS oncogene in bladder tumor progression.