Narrowing down the common deleted region of 5q to 6.0 Mb in blastic plasmacytoid dendritic cell neoplasms

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy. Simple and complex recurrent cytogenetic abnormalities have been reported, which demonstrate predominantly genomic losses, of which deletions of 5q are the most frequent aberrations in BPDCN with or without cutaneous manifestation; however, the gene responsible for the disease remains unknown. Using microarray-based molecular characterization, a recent study on several cases of BPDCN with the 5q deletion identified a large, common deleted region (CDR) of 29 Mb that contains several possible candidate genes. We report on a 67-year-old female patient who presented with leukemic BPDCN without skin involvement and had a deletion of 5q and a t(6;8)(p21;q24). By oligo-array-comparative genome hybridization (a-CGH) method, the genomic coordinations of the 5q deletion demonstrated unique breakpoints reported for the first time. Through mapping with those published cases using the same a-CGH method, the CDR was reduced from 29 Mb to 6 Mb, which excluded the previous candidate genes and highlighted an excellent biological gene: the HINT1 gene. Moreover, a molecular cytogenetic characterization of the translocation t(6;8) was performed in search for a novel gene fusion that could be associated with tumor progression.