Although deletions of CDKN2A/CDKN2B were significantly more common in Ph+ALL cell lines, the IC50s of 50 and 29 BCP-ALL cell lines with or without CDKN2A deletion (13.6 nM vs. 13.9 nM; 13.3 ± 5.5 nM vs. 15.0 ± 8.0 nM), respectively, were almost similar, and those of 54 and 25 BCP-ALL cell lines with or without CDKN2B deletion (13.7 nM vs. 13.7 nM; 13.6 ± 5.7 nM vs. 14.6 ± 8.2 nM), respectively, were identical (Table 1). This evidence concerns the gene CDKN2B and acute lymphoblastic leukemia.