Effect of 13-cis-retinoic acid on the spontaneous thymic lymphoma development in AKR mice.

The aim of the study was to analyze the incidence of spontaneous thymic lymphomas in AKR mice kept on a diet with normal and excess retinoid content. The mice whose diet was supplemented with 13-cis-retinoic acid (250 mg per kg chow) developed less lymphomas than those kept on a standard diet (15 mg per kg chow). The effect of cyclophosphamide on the early stage of lymphomogenesis was tested using a single dose (100 mg per kg body weight), injected intraperitoneally to AKR mice. Increased incidence of lymphoma following cyclophosphamide administration was observed as result of a) low sensitivity of prelymphoma and lymphoma cells and/or b) immunosuppressive effect of cyclophosphamide.