TEL/AML1 Fusion Transcripts in Childhood B-Lineage Acute Lymphoblastic Leukemia / 대한혈액학회지

ABSTRACT

BACKGROUND: The t(12;21)(p13;q22), which fuses the TEL gene on chromosome 12p13 and the AML1 gene on chromosome 21q22, is observed in approximately 20~25% of childhood B-lineage acute lymphoblastic leukemia (ALL) cases and is associated with a favorable outcome. A retrospective study was conducted to investigate the frequency of TEL/AML1 fusion in the patients diagnosed as childhood B-precursor ALL. METHODS: Because of the low detection rate by routine karyotypic analysis, we studied 54 children with B-lineage ALL using the fluorescence in situ hybridization (FISH) analysis. RESULTS: Results of this analysis demonstrated a 9.3% frequency of TEL/AML1 fusion, relatively lower than Japanese, Taiwanese and Caucasian children. All five patients with TEL/AML1 fusion showed CD10 positivity and predominance of male patients (41). Two cases of TEL/AML1 positive groups expressed the myeloid antigens, but no significance was noted (P>0.05). In TEL/AML1 positive groups, the leukemia was developed between 4 and 5 years old age (favorable age) and showed low initial leukocyte counts (<50,000/micro L). CONCLUSION: Although these findings combined with earlier reports indicate that TEL/ AML1 fusion was frequent genetic abnormality in childhood ALL, relatively low frequency in Korean patients suggested the existence of geographic or racial variations in the genotype of ALL.