Expression of HOXB genes is significantly different in acute myeloid leukemia with a partial tandem duplication of MLL vs. a MLL translocation: A cross-laboratory study

In acute myeloid leukemia (AML), the mixed lineage leukemia (. MLL) gene may be rearranged to generate a partial tandem duplication (PTD), or fused to partner genes through a chromosomal translocation (t. MLL). In this study, we first explored the differentially expressed genes between . MLL-PTD and t. MLL using gene expression profiling of our cohort (15 . MLL-PTD and 10 t. MLL) and one published data set. The top 250 probes were chosen from each set, resulting in 29 common probes (21 unique genes) to both sets. The selected genes include four . HOXB genes, . HOXB2, . B3, . B5, and . B6. The expression values of these . HOXB genes significantly differ between . MLL-PTD and t. MLL cases. Clustering and classification analyses were thoroughly conducted to support our gene selection results. Second, as . MLL-PTD, . FLT3-ITD, and . NPM1 mutations are identified in AML with normal karyotypes, we briefly studied their impact on the . HOXB genes. Another contribution of this study is to demonstrate that using public data from other studies enriches samples for analysis and yields more conclusive results.