CELF2 and leukemia: Moreover, the percentage of leukemia cells from 17 to 24 days after transplantation showed accelerated leukemia development in Celf2 KO + MA9 mice (Fig. 2B), leading to markedly accelerated mortality in this group (Celf2 KO + MA9 mice median survival = 36 days; MA9 mice median survival = 50 days; log-rank test P < 0.0001; Fig. 2C).