[Thrombocytic reactions in experimentally induced neoplasms (author's transl)].

Strain XVII mice with Graffi virus induced leukemia of various hematological types showed a pronounced thrombocytopenia which was severe in erythroblastic leukemia and weaker in lymphatic ones. The thrombocytic reactions shortly following Friend and Rauscher virus applications and occurred 3 weeks after birth in AKR mice are not found in Graffi virus system. A significant preleukemic thrombocytopenia did appear only 8 weeks after Graffi virus infection. The origin of both the preleukemic and the secondary thrombocytic reactions are discussed. (XVII X AKR) F1 hybrids, neonatally treated with N-nitroso-N-methylurea (NMU), resulted also in a decline in the number of thrombocytes after manifestation of leukemia. In contrast to the expection following NMU treatment a preleukemic thrombocytopenia appeared as in viral leukemogenesis too. The possibility of a co-operation of oncogenic viruses in chemical carcinogenesis is considered.