IBTK and neoplasm: At the macroscopic level, a significant increase in the weight and volume of lymph nodes (Figure 1C,D,E) and spleen (Figure 1F,G,H) was observed in a cohort of 12- to 16-week-old Ibtk+/-Eμ-myc mice compared to Ibtk+/+Eμ-myc mice, after tumor onset.