Previous studies demonstrated that BPO can promote chemically initiated
tumor formation in SENCAR mice. In addition, a number of chemicals have been shown to promote and/or enhance UVR induced
carcinogenesis. This study examined the effect of BPO on UVR initiated
tumor formation. One hundred and forty-eight Uscd mice received 270 mJ/cm2 of UVB radiation to the posterior halves of their backs 3 times a week for 8 weeks. Four weeks later the mice were divided into 4 groups. Group I received
croton oil in
acetone applications to the back 5 times a week for the duration of the study. Group II received
acetone, Group III received the BPO diluent, and Group IV received the BPO in an aqueous diluent applications as in Group I. One mouse in Group II (
acetone) and one in Group IV (BPO) developed
tumors in unirradiated skin. In the UVR initiated skin 38% of the survivors developed
tumors in Group I (
croton oil), whereas 5% did in Group II (
acetone), 8% in Group III (BPO base), and 8% group IV (BPO). Thus under the circumstances of this study
croton oil did promote UV initiated
tumor formation but BPO did not. These results are consistent with those recently reported by Iversen.