SHORT COMMUNICATION: TPA decreases the p53 response to benzo[a]pyrene-DNA adducts in vivo in mouse skin

TPA, a well-known tumor promoter, decreased the response ofnuclear P⁵³ immunoreactivity to benzo[a]pyrene-7, 8-diol-9,10-epoxide (BPDE)-DNA adducts in C57BL/6 mouse skin in vivo.A dose-dependent increase in both the level of BPDE-DNA adductsand nuclear p⁵³ immunoreactivity was found in mice treated topicallywith 50–750 µg benzo[a]pyrene. Such a positive correlationbetween the adducts and p53 positivity was suggested by an earlierstudy. Since p⁵³ probably functions in DNA damage control, interferenceby TPA with the p53 response could be a mechanism in TPA- inducedtumor promotion. Whether such a mechanism is more general intumor promotion deserves further study.