Clinical characteristics,immunophenotype,risk stratification and cytogenetics abnormalities in pediatric CDKN2A-deleted ALL
Of 655 patients enrolled, CDKN2A deletion was presented in 111 cases(16.9%). The prevalence of CDKN2A gene deletion in B-ALL and T-ALL was 14.6%(87/595) and 40.0%,respectively.In the CDKN2A-deletedpatients,the median age at diagnosis was 7 years(range:0.6 to 14 years),male/female(M/F) ratio was 1.47/1.The median white blood cell(WBC) countswere35.2×109/L(range:0.7-565.8×109/L),63.1%(70/111)patients had hepatosplenomegaly at diagnosis.
In our cohort,eighty-seven (78.4%) children were presented withB-cell phenotype while 24(21.6%) children were identified asT-cell phenotype.Based onCCLG-ALL 2015 risk stratification and bone marrow MRD level during induction therapy,there were 35(31.5%),73(65.8%),3(2.7%) case for standard group, intermedium groupand high-risk group,respectively.Our research showed the high proportion of intermedium group in patients with CDKN2A deletion.
Cytogenetic and molecular analysis was available inall subjects and exhibited 41 (42.3%) cases hadco-occurrence of fusion gene:TEL-AML1 (n=13,11.7%),BCR-ABL1(n=14,12.6%),E2A-PBX1(n=4,3.6%),SIL-TAL1(n=5,4.5%),P53(n=3,2.7%),MLLrearrangement(n=1,0.9%),E2A-HLF(n=1,0.9%),other fusion gene(n=6,5.4%)(Fig.1A). n=40(46.9 %) B-ALL cases had co-occurrence of fusion gene:TEL-AML1 (n=13,14.9%),BCR-ABL1 (n=14,16.1%),E2A-PBX1 (n=4,4.6%),P53(n=3,3.4%),E2A-HLF(n=1,1.1%),other fusion gene(n=5,5.7%)(Fig. 1B).To further analyze the role of co-occurrence of fusion gene in prognosis,n=17(15.3%) children were set to high risk cytogenetic group,remaining n=94(84.7%) children were set to intermediate cytogenetic group based on cytogenetic risk group as mentioned above.Besides,12.4%(12/97) had co-occurrence ofIKZF1 deletion.Chromosomal abnormalities was observed in 41 patients(36.9%) at diagnosis, including 10 cases(9.0%) with del(9)(p21) (Table 1).