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Background: The chromosomal translocation t(11;14)(q13;q32) is the hallmark of mantle cell lymphoma (MCL) in which it can be detected cytogenetically in about 75% of cases. The t(11;14) translocation juxtaposes the bcl-1 locus in chromosome band 11q13 next to the IgH locus in chromosome band 14q32 and, thus, leads to deregulation of the cell cycle regulatory protein cyclin D1, which is encoded by the CCND1 gene localized at the telomeric border of the bcl-1-locus. MCL has the worst prognosis of all low-grade non-Hodgkin's lymphomas (NHL). In some instances, however, histopathologic differentiation between MCL and other low-grade B-cell NHL is difficult. Therefore, detection of the t(11;14) translocation is of essential diagnostic value for the risk-adjusted management of patients with MCL. Unfortunately, chromosome analyses are frequently hampered by the low yield and quality of tumor metaphases. As the 11q13 breakpoints are scattered over a region of more than 120 kb the application of molecular genetic techniques is also limited., Patients and Methods: We established an interphase fluorescence in situ hybridization (FISH) approach for the detection of the t(11;14) translocation by use of a cosmid probe hybridizing to the IgH constant region and a YAC spanning the bcl-1 region. Cells containing a t(11;14) translocation show a colocalisation of the signals for IgH and bcl-1. Eight control samples and 15 MCL specimens were investigated., Results: According to our control studies, samples containing more than 10% of cells with this signal constellation can be diagnosed as carrying a clonal t(11;14) translocation. All eleven MCL found to carry the t(11;14) translocation by chromosome analysis were positive in our FISH assay. Additionally, two of four MCL lacking a clonal t(11;14) translocation by chromosome analysis were shown to carry this aberration in 14% and 37% of interphase nuclei. Southern blot data indicate that our FISH assay reliably detects the t(11;14) translocation irrespective of the location of the breakpoints within the bcl-1 region., Conclusions: The described interphase FISH assay provides a reliable and routinely applicable tool for diagnosis of the t(11;14) translocation.

The translocation t(8;14)(q24;q32) is the characteristic chromosomal aberration of Burkitt's-type lymphomas and leukemias (BLs). On the molecular level, the t(8;14) juxtaposes the c-myc gene in 8q24 next to the IgH locus in 14q32, resulting in overexpression of the transcription factor c-Myc. The detection of a t(8;14) is a major aim in the diagnostic process of all patients with high-grade B-cell lymphomas because treatment strategies differ between BL and other high-grade lymphomas. As chromosome analyses are sometimes hampered by the low yield or poor quality of metaphase spreads and as the application of molecular genetic techniques is limited by the distribution of the 8q24 breakpoints over a region of about some hundred kilobases, we set out to establish an interphase fluorescence in situ hybridization (FISH) assay for the detection of the t(8;14). A cosmid probe hybridizing to the IgH constant region in 14q32 was combined with a differently labeled probe of pooled cosmid clones spanning the c-myc locus in 8q24. Interphase nuclei lacking a t(8;14) show two separated signals corresponding to each probe, whereas interphase nuclei carrying a t(8;14) display a split of the c-myc probe and a colocalization of at least one of the splitted signals with the IgH probe. Based on the results of extensive control studies, the cutoff level for this stringent (type I) criteria was set at 2%. Additionally, colocalization of at least one c-myc signal with one IgH signal alone (without signal split for the c-myc probe) was used as a less stringent (type II) criteria with a cutoff limit of 11%. Nine BLs and one Burkitt-like lymphoma were investigated by this approach. Cytogenetically, all tumors contained a translocation t(8;14)(q24;q32) except for one BL, in which cytogenetic analysis had failed. In interphase FISH, all lymphomas and leukemias met the less stringent criteria for the diagnosis of the t(8;14). Additionally, in all tumors but the Burkitt-like lymphoma, a t(8;14) could be diagnosed according to the stringent criteria. The percentage of cells found to harbor the t(8;14) by FISH ranged from 4.3% to 100%. Comparison of cytogenetic and FISH results revealed a significantly lower percentage of t(8;14)+ interphase nuclei than metaphase cells (P = .004). In conclusion, the described FISH assay provides a feasible and sensitive tool for the routine detection of the translocation t(8;14) in interphase cells which might also offer new insights into the biology of high-grade B-cell lymphomas.

Purpose: The aim of this study was to establish a fluorescence in situ hybridization (FISH) technique for the detection of t(14;18)(q32;q21), characteristic for follicular lymphoma (Kiel classification: centroblastic centrocytic [cb-cc] lymphoma)., Materials and Methods: After the FISH system had been established, parallel studies of lymph node biopsy specimens from 30 patients with cb-cc lymphoma and from 32 patients with nonneoplastic lymphoproliferation were performed by means of chromosome analysis, polymerase chain reaction (PCR), and FISH analysis. Two differently labeled yeast-artificial-chromosome (YAC) probes that contained the entire bcl-2 gene and the C-region of the immunoglobulin H (IgH) gene, respectively, were used to detect t(14;18) by FISH., Results: The presence of the translocation is indicated by a red (Cy3)/green (fluorescien isothiocyanate [FITC]) double signal, which corresponds to the IgH/bcl-2 fusion gene, whereas in normal cells the signals are separate. Control studies showed that the double signal is visible in less than 1% of normal cells. FISH analysis was able to identify the t(14;18) in all cases of cb-cc lymphoma we studied. All bcl-2 breakpoints can be detected. Combined immunophenotyping and interphase cytogenetics demonstrated that t(14;18) was restricted to CD22+ B lymphocytes and never occurred in CD3+ T lymphocytes. In four of 32 cases of nonneoplastic lymphoproliferation, t(14;18) was also detected., Conclusion: FISH turned out to be the most sensitive method to detect t(14;18). Our FISH results confirm PCR data from other groups that found evidence for the presence of t(14;18) in nonneoplastic lymphoproliferation. It needs to be determined whether, in morphologically nonneoplastic processes, t(14;18) is associated with an increased risk for the development of non-Hodgkin's lymphoma.

Little is known about the clinical significance of secondary chromosome aberrations in lymphomas with t(11;14)(q13;q32), the characteristic change of mantle cell lymphomas. Here we present a patient with mantle cell lymphoma, who showed a variant Burkitt's translocation t(2;8)(p12;q24) in addition to t(11;14) during the progression of the disease. An involvement of chromosome 8q24, the localization of the c-myc gene, has so far been described in only four patients, who seemed to have a fatal clinical course. Although no blastic transformation occurred in our patient, no remission could be induce by intensified treatment and survival was only 5 months. This case demonstrates that secondary chromosome aberrations can determine the clinical course of patients, even if morphologic and immunophenotypic findings fail to predict the poor outcome.

The t(11;14)(q13;q32) translocation is a consistent chromosome change in mantle cell lymphomas. This study investigates the application of fluorescent in situ hybridization (FISH) with chromosome painting probes for interphase cytogenetic analysis in patients with mantle cell lymphomas. Chromosome 11 paints have been able to show splitting of the chromosome signal consistent with the t(11;14) translocation in interphase cells from bone marrow and blood of patients with mantle cell lymphomas. These include some in clinical remission. The chromosome probes conjugated with fluorescent molecules are hybridized with patient's DNA allowing the easy detection of chromosome 11 abnormalities with fluorescent-light microscopes. Interphase FISH has a higher sensitivity and is quicker than standard metaphase cytogenetics. This may be beneficial in rapid detection of chromosome 11 abnormalities, assisting in the diagnosis of mantle cell lymphomas. In addition, detection of a clonal population of cells is possible.