IBTK and lymphoma: While the complete loss of Ibtk (Ibtk-/-Eμ-myc mice) delayed the lymphoma onset and increased the lifespan, the loss of a single allele of Ibtk (Ibtk+/- Eμ-myc mice) did not significantly affect tumor onset and the median age of mortality in Eμ-myc mice littermates [22].