IGH gene involvement in two cases of acute lymphoblastic leukemia with t(14;14)(q11;q32) identified by sequential R-banding and fluorescence in situ hybridization

Translocation (14;14)(q11;q32) or inv(14)(q11q32) is a common cytogenetic aberration in T-cell leukemia associated with ataxia-telangiectasia (AT); however, rare reports have indicated that this abnormality also occurs in B-lineage acute lymphoblastic leukemia (ALL). We report here two cases with common-type ALL exhibiting the chromosomal aberration t(14;14)(q11;q32). The immunophenotype showed the blasts were positive for CD9, CD10, CD38, CD22, and CD15 in case 1 and positive for CD2, CD9, CD10, CD19, CD38, CD20, and CD22 in case 2, but negative for CD3, CD4, and CD8 expression in both cases. The cytogenetic analysis revealed del(6)(q22), and t(14;14)(q11;q32) in case 1 and t(14;14)(q11;q32),+mar in case 2. Fluorescence in situ hybridization (FISH) and sequential R-banding FISH assay with dual-color break-apart IGH probe confirmed that t(14;14)(q11;q32) involved the IGH gene in our cases. The results indicate that the t(14;14)(q11;q32) involving IGH at 14q32 in B-lineage ALL in our cases differ from those reported to involve the TCL1 gene on 14q32.1 in T-cell leukemia associated with AT. Sequential R-banding and FISH provide precise analysis of alterations of chromosomes and genes involved.