Diagnostic utility of fluorescence in situ hybridization in mantle-cell lymphoma

Mantle-cell lymphoma (MCL) has a poorer prognosis than other small B-cell l ymphomas, thus a definitive diagnosis is essential. The t(11;14)(q13;q32) a ssociated with MCL juxtaposes portions of CCND1 (11q13) and IGH (14q32), re sulting in over-expression of cyclin D1. In this study, a highly sensitive two-colour fluorescence in situ hybridization (FISH) method was developed t o detect t(11;14)(q13;q32) in nuclei isolated from paraffin-embedded tissue . Twenty-three MCLs, 13 normal controls and nine small B-cell lymphomas oth er than MCL were studied by FISH. Each MCL had been previously investigated to detect genomic IGH-CCND1 fusion by polymerase chain reaction (PCR) usin g DNA extracted from frozen tissue. The IGH-CCND1 fusion detection rate in the MCLs was 96% by FISH compared with 35% by PCR. By FISH, one MCL and thr ee small B-cell lymphomas other than MCL harboured abnormalities involving only IGH. Less than 1% of cells showed false-positive IGH-CCND1 fusion in n ormal specimens by FISH. Thus, this highly sensitive FISH assay is very use ful in confirming the diagnosis of MCL, has wide applicability as it may be performed on both paraffin-embedded and fresh tissue, and may also facilit ate detection of translocations involving these loci in tumours other than MCL.