Classical and Molecular Cytogenetic Abnormalities in 124 Pediatric Patients with Acute Lymphocyte Leukemia.

In childhood acute lymphocyte leukemia (ALL), cytogenetics plays an important role in diagnosis, allocation of treatment and prognosis. On base of the conventional cytogenetic analysis, molecular methods have inproved our ability to accurately and rapidly risk-stratify patient with childhood ALL in the last few years. Our aim was to assess the demography of cytogenetic abnormalities in childhood ALL. The study sample consisted of 124 newly diagnosed ALL patients younger than 16 years, who were diagnosed at the Department of Pediatric Hematology/Oncology, Soochow University Children’s Hospital. The diagnosis and FAB subtypes of ALL was determined by Wright-Giemsa-stained bone marrow smears and cytochemicalstaining. Immunophenotyping of the bone marrow samples was performed by flow cytometry. Multiplex reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed to detect the 29 most common leukemia translocations for routine molecular diagnostic hematopathology practice, and complement the information gained from conventional cytogenetic analysis. Cytogenetic analysis was successful in 112 of 124 children with ALL. Sixty-eight (60%)of them had clonal chromosomal abnormalities. Numerical imbalances consisted of hyperdipoild(>47 chromosomes, 36 cases), hypodipoild(<46 chromosomes, 14 cases), pseudodiploidy(18 cases). Chromosomal translocations were observed in 13 patients by conventional cytogenetic analysis. Three cases were found positive for t (4;11), 3 cases for t (9;22), 1 case for t (1;19) and 6 cases for other rare translocations. RT-PCR analysis detected 116 of the 124 ALL patients. Thirteen cases of TEL-AML1, 10 cases of rearrangement in the MLL gene, 4 cases of E2A-PBX1, 4 cases of E2A-HLF, 3 cases of BCR-ABL, 2 cases of TLS-ERG, 32 cases of HOX11, were detected by RT-PCR in B-lineage leukemias. SIL-TAL1 had been found in 4 of 7 of T-lineage leukemias. Sixty-eight cases of ALL show chromosomal aberrations. Multiplex PCR positivity was detected in 59(50%)of the 116 ALL patients studied. Multiplex PCR combined with chromosome analysis uncovered Chromosomal abnormalities in 95 of 124(77%) of ALL patients and supplemented each other in detecting Chromosomal abnormalities. It provides reliable evidence for the diagnosis, classification and prognosis.