T-cell acute lymphoblastic leukemia (T-ALL) presented with massive organomegaly and bone marrow involvement (Figure 1B) at a median latency of 230 days and 100% penetrance (Figure 1C) similar to what has been described in independently constructed CD2-Lmo2 transgenics; the latency was increased with backcrosses to B6 (Figure S5 in File S1) [24], [25]. Here, CD2 is linked to acute lymphoblastic leukemia.