CDKN2A and acute lymphoblastic leukemia: Indeed, all 14 of the Ph+ALL cell lines carried deletions of IKZF1, CDKN2A, and CDKN2B, while 11 (16.9%), 36 (55.4%), and 40 (61.5%) out of 65 Ph-negative BCP-ALL cell lines carried deletions of IKZF1, CDKN2A, and CDKN2B, respectively (S3 Table).