 Myc gene placed under the control of IgM heavy chain enhancer in transgenic mice gives rise to mainly lymphomas.Later on, in order to study effects of Myc in other types of cancer, transgenic mice that overexpress Myc in different tissues (liver, breast) were also made.In all these mouse models overexpression of Myc causes tumorigenesis, illustrating the potency of Myc oncogene.