CDKN2B and acute lymphoblastic leukemia: When we focused on homozygous deletions, the IC50 of 22 BCP-ALL cell lines with biallelic loss of CDKN2A (12.2 nM; 11.2 ± 5.0 nM) was significantly lower than that of 57 BCP-ALL cell lines with monoallelic or no loss of CDKN2A (13.9 nM; 15.0 ± 6.8 nM; p = 0.012) (Fig 2C), while that of 22 BCP-ALL cell lines with biallelic loss of CDKN2B (13.6 nM; 13.1 ± 6.7 nM) was almost similar to that of 57 BCP-ALL cell lines with monoallelic or no loss of CDKN2B (13.9 nM; 14.2 ± 6.5 nM) (data not shown).