OBJECTIVETo evaluate the copy number variations (CNVs) in pediatric ETV6/RUNX1 gene positive acute lymphoblastic leukemia(ALL) and its correlation with clinical features and prognosis.

METHODTotally 141 children (<14 years of age) with newly diagnosed ETV6/RUNX1 positive ALL in Institute of Hematology and Blood Diseases Hospital, were included from January 2006 to November 2012. The CNVs were analyzed by multiplex ligation-dependent probe amplification (MLPA). The survival rate between the patients with CNVs were explored. Overall survival (OS) and event-free survival (EFS) were estimated by the Kaplan-Meier method and compared with the log-rank test.

RESULTAmong the 141 cases, 55.3% (n=78) were boys and 44.7% (n=63) were girls and the median age was 4 (1-13) years. The estimated 5-year DFS rate for the patients was (84±4)%. The estimated 5-year OS rate for the patients was (85±4)%. Ninety-five patients were tested MLPA. CNVs were detected in 73 cases (76.8%). CNVs of genes EBF1(15.8%), CDKN2A/2B(18.9%), PAX5(21.1%), ETV6(54.8%), BTG1(10.5%) were detected in more than 10% of the patients. Among the 95 patients, EBF1 deletions were found in 9 patients and EBF1 amplifications were found in 6 patients; 5-year recurrence-free survival (RFS) was statistically significant among 3 groups (χ(2)=9.809, P=0.007) . PAX5 deletions were found in 13 patients and PAX5 amplifications were found in 7 patients; the difference in 5-year RFS was statistically significant between 3 groups(χ(2)=7.622, P=0.022). ETV6 deletions were found in 39 patients and ETV6 amplifications were found in 13 patients; the difference in 5-year RFS was statistically significant among the 3 groups (χ(2)=11.045, P=0.004).

CONCLUSIONThe CNVs had prognostic relevance in ETV6/RUNX1 positive ALL.