Correlation of karyotype and immunophenotype in childhood acute lymphoblastic leukemia; experience at the National Cancer Institute, Cairo University, Egypt.

PURPOSE To identify chromosomal pattern among the major immunophenotypic subgroups in Egyptian children with ALL, and its correlation with clinical presentation and disease free survival. PATIENTS AND METHODS Cytogenetic and immunophenotypic analysis were done for all patients. Patients received ALL-PNCI-III/98 chemotherapy protocol used at NCI, Cairo University. RESULTS The frequency of pseudodiploidy and normal karyotype in the whole group was 42.9% and 33.3% respectively. The frequency of pseudodiploidy was 36.8% in CALLA positive early pre B, 30.7% in pre B cases, 71.4% in T cell cases and 100% in mature B cell cases. At 12 months, DFS was 50% for pseudodiploid group having pre B phenotype, compared to 16.6% for pseudodiploid group with CALLA positive early pre B ALL. Sixteen percent of the studied cases showed T cell phenotype, 71.4% of them showed pseudodiploid karyotype, all of them had high risk features. Hyperdiploidy was found in 31.5% of CALLA positive early pre B cases and was associated with favorable prognostic features and DFS of 66.6% at 12 months. Hyperdiploidy of >50 chromosome represented 62.5% of hyperdipoid cases, 80% of them were CALLA positive early pre B ALL carrying good risk features. Fifty percent of normal karyotypic patients showed pre B phenotype, while 42.8% showed CALLA positive early pre B ALL. Their age, TLC, DFS, were almost comparable. CONCLUSION CALLA early pre B phenotype has a positive impact on chromosomal pattern having best outcome among patients with hyperdiploidy. The Pseudodiploid karyotype carries a better outcome with pre B phenotype.