Multistage Mastocytoma Model Characterized by Autocrine IL-3 Production

Leukaemogenesis, as tumor formation in general, is a multistage process where alterations of proto-oncogenes play some yet unknown role. To understand this process, it is necessary to know how activated proto-oncogenes (i.e., oncogenes) affect and perturb cellular growth control mechanisms from extracellular growth factors down the signal transduction pathway to the nucleus. We and others have previously reported [1, 2] that one of the frequent proto-oncogene alterations in human leukemias and lymphomas are point mutations of the ras genes (predominantly N-ras), findings which have led us to ask how an activated ras gene might affect responsiveness to hemopoietic growth factors.