Cryptic insertion producing two NUP98/NSD1 chimeric transcripts in adult refractory anemia with an excess of blasts.

We performed cytogenetic and molecular studies on an adult patient with refractory anemia with an excess of blasts with an add(11)(p15). Multicolor fluorescence in situ hybridization (FISH) identified the extra material on 11p as belonging to chromosome 15. Metaphase FISH with probes for chromosomes 5, 11, and 15 revealed a complex four-break rearrangement.