CDKN2B and precursor B-cell acute lymphoblastic leukemia: Both groups of B-ALL patients shared recurrent CNAs on IKZF1/7p12.2; CDKN2A, CDKN2B, IFN, MTAP/ 9p21.3; BTG1/12q21.33; MTA1/14q32.33, VPREB1/22q11.22 and IL3RA, CRLF2, CSF2RA, CSF2RA, P2RY8, ASMTL and SLC25A6/ Xp22.33 loci.