DCK and acute lymphoblastic leukemia: However, the association of clofarabine sensitivity with DCK gene expression in 79 BCP‐ALL cell lines was marginal (Fig. 7C); the IC50 values of clofarabine in 40 cell lines with relatively higher DCK gene expression (median IC50; 6.3 ng/mL) were slightly lower (P = 0.044) than those in 39 cell lines with lower DCK gene expression (11.1 ng/mL).