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

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 (4:1). 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.

The Outcome of Philadelphia Chromosome-Positive Adult ALL: Characteristics and Prognosis / Journal of the Korean Cancer Association, 대한암학회지

The Philadelphia (Ph) chromosome is a well- known chromosome abnormality in adults with B-lineage ALL, and is associated with a poor prognosis. This study compared the clinical manifestations and prognosis in adult Ph-positive and Ph-negative ALL patients. MATERIALS AND METHODS: We retrospectively analyzed the clinical records of adult patients newly diagnosed as B-lineage ALL, between January 1995 and February 2001. Fifty five patients were included in this study. We divided the patients into Ph-positive and Ph-negative groups. RESULTS: Eighteen of the 55 patients (32.7%) were found to have the Ph chromosome. At initial diagnosis, the Ph-positive patients had higher circulating leukocyte counts, lower platelet counts and had a greater tendency to bleed, than the Ph-negative group. The complete remission rates were 83.3% and 83.8% for the Ph-positive and the Ph-negative groups, respectively. Four of the Ph-positive, and 13 of the Ph-negative, patients underwent allogenic bone marrow transplantation. The median follow-up for the surviving patients was 39.3 months. The three-year survival rates were 10.4% and 51.8% for the Ph-positive and the Ph-negative groups, respectively. The median disease-free survival was 7.7 months for the Ph-positive group, but did not reach the median value in the Ph-negative group. Among the Ph-positive patients, age was the only factor that had an impact on the disease outcome. CONCLUSION: In adult B-lineage ALL, the Ph-positive patients had similar complete remission rates to other patients; however, the remission was of shorter duration, with a higher relapse rate in the Ph-positive patients. More effective treatments are needed to improve the survival of the Ph-positive patients.

Clinical Significance of Membrane CD22 in B-lineage Acute Lymphoblastic Leukemia / 대한임상병리학회지

BACKGROUND: CD22 is a glycoprotein expressed on the surface of normal mature B cells and in the cytoplasm of normal B cell precursors. Cytoplasmic CD22 (cCD22) has been proposed as a immunologic marker for the diagnosis of B-lineage acute lymphoblastic leukemia (ALL) while membrane CD22 (mCD22) has been used as the marker for chronic lymphocytic leukemia, B-lineage lymphoma, and hairly cell leukemia, and mCD22 has not been routinely used for the diagnosis and subgrouping of ALL. The purpose of this study was to examine the expression of mCD22 in B-lineage ALL and its clinical significance. METHODS: From 1992 to April, 1998, the leukemic cells of 64 patients newly diagnosed as B-lineage ALL by immunophenotyping were analyzed by the direct immunofluorescence method using monoclonal antibodies including mCD22. RESULTS: mCD22 was positive in 53% (34/64) of all patients, 50% (21/42) of children and 59% (13/22) of adults. According to the immunologic classification, mCD22 was positive in 44% (4/9) of group II, 53% (19/36) of group III, 69% (11/16) of group IV, but negative in 3 cases of group V and VI. The complete remission rate of the mCD22 negative group in group III was significantly higher than that of the mCD22 positive group (P=0.008). There were significant differences in survival rates between the mCD22 positive group and the mCD22 negative group in group II, III and IV (P=0.046) and the above observed significant difference was seen when group III was separately tested (P=0.014). CONCLUSIONS: Our study demonstrated that the expression of mCD22 may be a poor prognostic factor in B-lineage ALL and that mCD22 shall be clinically used as a prognostic marker especially in group III, which is most common among the subgroups of B-lineage ALL.