High-resolution multicolor banding (mBAND) analysis was applied to precisely fine-map the genomic extent of 7q deletions in a series of 26 marginal zone lymphoma patients displaying the abnormality on conventional karyotypes. Using this approach, the breakpoints and the extent of deletions revealed by conventional banding techniques had to be re-defined in 70% of cases. Although no common minimal region of deletion was delineated, mBAND demonstrated the involvement of the 7q32 region in more than 90% of cases. In addition, unsuspected translocations and intrachromosomal changes could be identified in four cases. Taken together, these data demonstrate that mBAND represents an alternative cytogenetic tool in the comprehensive analysis of chromosome aberrations in hematologic malignancies, allowing rapid screening and precise delineation of structural rearrangements of a defined chromosome. This also confirms the localization in the vicinity of band 7q32 of putative candidate gene(s) involved in the pathogenic development of the disease.