Molecular cloning of the breakpoints of a t(10;14)(q24;q32) chromosomal translocation in a case of B-cell lymphoma identified the NKX2-3 gene in chromosome 10q24.2 juxtaposed to the IG heavy-chain (IGH) gene in 14q32.33, resulting in increased NKX2-3 expression. This evidence concerns the gene NKX2-3 and B-cell non-Hodgkin lymphoma.