Transgenic Myc expression driven by the IgH enhancer (Eμ-Myc) results in spontaneous lymphomas presenting as lymphadenopathy, as well as pre-B cell leukemias early in life (3–18 wk, median 9 wk of age) (Adams et al., 1985; Harris et al., 1988). This evidence concerns the gene MYC and Lymphadenopathy.