Role of BAALC Gene in Prognosis of Acute Lymphoblastic Leukemia in Egyptian Children.

Abstract

Acute lymphoblastic leukemia (ALL) is characterized by excess bone marrow lymphoblast cell production. Brain and Acute Leukemia Cytoplasmic gene (BAALC gene) is a recently identified gene on chromosome 8q22.3. The aim of this work was to study the role of BAALC gene in prognosis of ALL in Egyptian children. This study was conducted on 60 children with ALL who were admitted in Oncology Unit in the period from January 2012 to March 2015 including 36 males and 24 females with mean age of 8.74±2.66years. For all patients the following were done: Full history taking, thorough clinical examination and laboratory investigations including: complete blood count, LDH, bone marrow aspiration, cytochemistry, immunophenotyping, FISH technique for detection of t(12;21) and t(9;22) and assessment of BAALC gene expression by PCR in bone marrow aspirate mononuclear cells at diagnosis before chemotherapy. Positive BAALC gene expression was found in 36 patients (60%) and negative expression in 24 patients (40%). Positive BAALC gene expression group includes 14 males and 22 females with mean age at presentation of 8.45±2.77years while negative BAALC gene expression group includes 18 males and 6 females with mean age at presentation of 8.61±2.44years with no significant differences between positive and negative BAALC gene expression groups regarding age, sex, clinical presentations, WBCs and platelets counts, hemoglobin and LDH levels, peripheral blood and BM blast cell counts, immunophenotyping and chromosomal translocations including t(12;21) and t(9;22). There were significant differences in disease outcome between positive and negative BAALC gene expression groups with higher rate of relapse and death and lower rate of complete remission, disease free survival (DFS) and overall survival (OS) in positive BAALC gene expression group compared with negative group (p=0.028). Multivariate analyses for overall survival and disease free survival shows significant role of BAALC gene expression in OS and DFS. BAALC expression might represent an additional prognostic marker in children with ALL and should be routinely assessed at diagnosis for better prognostic assessment.