Deletion in 9q34 in abnormal karyotype (AK) precursor B adult acute lymphoblastic leukemia (B-ALL)

Recurrent deletion in the chromosomal region 9q34 has recently been described in adult normal karyotype (NK) precursor B-cell acute lymphoblastic leukemia (B-ALL). This deletion involves the genes SET, NUP188, ABL1, NUP214 and results in the likely juxtaposition of the SET and the NUP214 genes. The SET-NUP214 fusion protein appears to promote elevated expression of HOXA cluster genes that may play a role in ALL pathogenesis. We asked whether deletions in 9q34 occur in abnormal karyotype (AK) adult B-ALL patient samples. Fluorescent insitu hybridization (FISH) studies using a bacterial artificial chromosome (BAC) clone probe specific for NUP188 (RP11-184E19) were used to identify 9q34 deletion. A centromeric probe for chromosome 9 was used in all experiments as an internal control. Deletions were found in 11/63 (17.46%) cases examined. These results suggest that deletion of NUP188 and hence deletion in 9q34 occurs in AK as well as NK B-ALL. Correlation with patient outcomes would be needed to determine the prognostic significance of this deletion and the FISH results need to be further delineated by single nucleotide polymorphism (SNP) arrays/genomic sequencing to determine the exact breakpoints of the deletion.