During the discovery of Myc gene, it was realized that chromosomes that reciprocally translocate to chromosome 8 contained immunoglobulin genes at the break-point. To study the mechanism of tumorigenesis in Burkitt lymphoma by mimicking expression pattern of Myc in these cancer cells, transgenic mouse models were developed. 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.