The in vivo investigation of onco/suppressor gene effects may provide new information on chemical-environmental carcinogenesis. We previously described the elevation of onco/suppressor gene expression due to CHOP and COPP chemotherapeutical protocols in a CBA/Ca mouse model. Below we describe the results of the onco/suppressor gene expression studies after treatment with ABVD, a non-cyclophosphamide containing protocol. Expression of c-myc, Ha-ras, and p53 genes was investigated 1/2, 1, 3, 6, 12, 24 hours, 2 6 30 days, 6, and 12 months after treatment with a single dose of ABVD protocol. RNA was isolated from the thymus, spleen, liver, bone marrow, kidneys, and hybridzed with chemiluminescently labelled probes of Ha-ras, c-myc, and p53 genes. Significant changes of gene expression was found in the spleen and thymus, even after 30 minutes. The female spleen seemed to be more sensitive than the male one, but no sex difference was observed in the thymus. No significant alteration was detected in the other investigated organs.