Analysis of clinical characteristics and prognosis of newly-treated acute lymphoblastic leukemia patients with MLL-AF4 fusion gene-positive / 白血病·淋巴瘤

ABSTRACT

Objective:To investigate the development of MLL-AF4 fusion gene-positive in newly-treated acute lymphoblastic leukemia (ALL) and to analyze the clinical characteristics and prognosis of patients with MLL-AF4 fusion gene-positive ALL.Methods:The clinical data of 455 patients with primary newly-treated ALL from February 2010 to February 2021 in Zhumadian Central Hospital were retrospectively analyzed. Fluorescence in situ hybridization was used to detect the presence of MLL gene rearrangement, and multiplexed nested reverse transcription polymerase chain reaction was used to detect the development of MLL-AF4 fusion gene-positive, and to compare the clinical characteristics and prognosis of patients with positive and negative MLL-AF4 fusion gene.Results:Among 455 patients with primary newly-treated ALL, 30 cases (6.6%) were positive for MLL gene rearrangement, including 21 positive for MLL-AF4 fusion gene (MLL-AF4 positive group), 6 cases positive for MLL-ENL fusion gene, 2 cases positive for MLL-AF9 fusion gene, and 1 case positive for MLL-AF10 fusion gene. A total of 60 ALL patients without any detection of fusion gene during the same period were randomly selected as the MLL-AF4-negative group. The proportion of those with hepatomegaly or splenomegaly, central nervous system (CNS) invasion, and the median peripheral blood leukocyte count and median peripheral blood na?ve cells absolute value in the MLL-AF4-positive group were higher than those in the MLL-AF4-negative group (all P < 0.05). The complete remission rates on day 15 of chemotherapy were 81.0% (17/21) and 90.0% (54/60), respectively in the MLL-AF4-positive group and MLL-AF4-negative group ( χ2 = 0.49, P = 0.484), and the cumulative relapse rates of 3 months were 38.1% (8/21) and 13.3% (8/60), respectively in the MLL-AF4-positive group and MLL-AF4-negative group ( χ2 = 4.56, P = 0.033). The overall survival in the MLL-AF4-positive group was worse than that in the MLL-AF4-negative group ( χ2 = 5.93, P = 0.015). Conclusions:Patients with MLL-AF4 fusion gene-positive ALL have a higher tumor load, a higher recurrence rate, a lower overall survival rate, and a poorer prognosis compared with negative patients at the initial diagnosis.