[Clinical Features and Prognosis of Acute Lymphoblastic Leukemia Children with P2RY8-CRLF2 Gene Rearrangement].

Objective: To investigate the clinical features and prognostic factors of acute lymphoblastic leukemia (ALL) children with P2RY8-CRLF2 gene rearrangement.

Methods: A total of 108 children with B-cell ALL (B-ALL) were diagnosed and systematically treated according to Chinese Children's Leukemia Group (CCLG) -ALL 2008 in our hospital from January 2016 to December 2016. The 108 patients were divided into two groups according to the result of mutiplex polymerase chain reaction: group with P2RY8-CRLF2 gene rearrangement and group without P2RY8-CRLF2 gene rearrangement. The ALL children with P2RY8-CRLF2 gene rearrangement were all treated by CCLG-ALL 2008 high-risk group (HR) regimens, and the ALL children in group without P2RY8-CRLF2 gene rearrangement received different intensity chemotherapy according to clinical risk classification.

Results: Five (4 male and 1 female) out of 108 patients with B-ALL had P2RY8-CRLF2 gene rearrangement. In the 5 B-ALL patients with P2RY8-CRLF2 gene rearrangement, the median age of the was 4 (2-6) years old and the median WBC count was 26.2 (2.46-525.1)×10/L. These patients presented different immunophenotype, including 3 cases of common B-ALL and 2 cases of pre B-ALL. Four patients carried a normal karyotype and 1 patient carried 46, XY, der (20) [22]/46, XY[2]. For the children with P2RY8-CRLF2 gene rearrangement, 1 patient (20%) could not achieve complete remission (CR), and minimal residual disease (MRD) of 2 patients (40%) was higher than 1% on day 33 of induction chemotherapy; while in group without P2RY8-CRLF2 gene rearrangement, all the patient achieved CR, and MRD in 6 patients (5.8%) was higher than 1% on day 33 of induction chemotherapy. The 3 year event-free survival (EFS) of ALL children in group with P2RY8-CRLF2 gene rearrangement was significantly lower than that in group without P2RY8-CRLF2 gene rearrangement (60.0%±21.9% vs 85.9%±3.9%) (P<0.05).

Conclusion: The early treatment response and prognosis of ALL children with P2RY8-CRLF2 gene rearrangement are worse, and more effective protocol is needed for this subtype patients.