Comparison of early onco/suppressor gene expressions in peripheral leukocytes and potential target organs of rats exposed to the carcinogen 1-nitropyrene

An in-vivo model has been developed to study early expressions of c-myc, Ha -ras oncogenes and p53 suppressor gene as biomarkers of carcinogenic exposu re and/or tumorigenesis. In order to validate the in-vivo expression change s as biomarkers, rats were treated with the outdoor air pollutant carcinoge n 1-nitropyrene. The gene expression levels were measured after 24 and 48 h in potential target tissues (lung, liver, lymph nodes, kidneys, spleen) an d in peripheral blood leukocytes. Another main objective was to prove the a pplicability of leukocytes as a surrogate tissue, having a similar expressi on pattern of the selected genes upon carcinogenic exposure. The c-myc onco gene was not suitable as an early biomarker because of the lack or low leve l of its expression. However, in the ease of the other oncogene Ha-ras and the suppressor gene p53, remarkable and early changes were detected in the expression signals, Similar expression patterns could only be detected in l eukocytes and the spleen; therefore we continue this validation study by us ing other types and routes of exposure. (C) 2000 Lippincott Williams & Wilk ins.