Coexpression of MYC and BCL-XL or BCL-2 strongly favored tumor development towards myeloid leukemia, whereas coexpression of MYC and FLIPL did not affect the distribution of myeloid versus lymphoid tumor cells, but changed the ratio between single CD4+ and double positive CD4+CD8+ T-cell lymphomas. This evidence concerns the gene BCL2 and lymphoid neoplasm.