- Cellular DNA regions involved in the induction of rat thymic lymphomas (Mlvi-1, Mlvi-2, Mlvi-3, and c-myc) represent independent loci as determined by their chromosomal map location in the rat. Tsichlis, P.N., Lohse, M.A., Szpirer, C., Szpirer, J., Levan, G. J. Virol. (1985)