Jalal, Syed M.

Abstract Fluorescence in situ hybridization (FISH) is an effective alternative for the analysis of cytogenetic abnormalities of low proliferative entities such as Waldenström macroglobulinemia (WM) but, to date, no studies have been carried out to explore the potential impact of molecular cytogenetics on disease evolution. Deletion of the long arm of chromosome 6 (6q-) is the most frequent cytogenetic abnormality in WM. In this study we have analyzed the incidence of this aberration (using both conventional cytogenetics and FISH analysis) in 102 WM patients, and we have correlated it with disease characteristics. Deletion of 6q21 was detected in 6% of patients by conventional cytogenetics, while FISH studies increased this incidence up to 39%. Moreover, in those patients analyzed by cIgM-FISH, the incidence of 6q- was higher (54%). Interestingly, 6q- patients displayed features associated with adverse prognosis (higher levels of ESR, CRP and beta-2 microglobulin), and a greater tendency to display anemia and hypoalbuminemia. Other differentiating variables without reaching statistical significance were a tendency of displaying a higher bone marrow lymphoplasmacytoid infiltration and the amount of monoclonal component in 6q- patients (table). In addition, patients with 6q- displayed shorter survival from time of diagnose (log-rank; p=0.09). In summary, our results show that 6q deletion in WM patients is currently the most frequently found cytogenetic abnormality. Patients with this deletion also shows a trend towards an aggressive disease and poorer outcome in WM. Further studies should focus on possible tumor suppressor genes in the minimal area of deletion at 6q and to determine their role in disease progression. table del6q present del6q absent p-value n 40 (39%) 62 (61%) β2M ≥4mg/dL 48% 16% 0.005 CRP ≥3.5 mg/dL 47% 11% 0.006 Albumin <4mg/dL 86% 55% 0.006 ESR ≥100 mm/h 73% 44% 0.02 Hb <11 g/dL 63% 40% 0.02 serum IgM >20 g/L 86% 73% 0.10 BM infiltration >40% 44% 31% 0.20

Abstract H-MM affects about 40–50% of patients, and a similar proportion of MGUS/SMM. The genetic evolution of the disease and the clinical implications of the co-existence of 13q- or t(14q32) are unknown. We conducted a global survey of genetic abnormalities in H-MM in order to describe genetic evolution pathways. H-MM cases from the Mitelman cancer genetic database were combined with cases from the Mayo Clinic MM genetic database. All abnormalities (regional/whole chromosome gains/losses, breakpoints and translocations) were plotted against a 344-chromosome band profile created in a matrix format, and the number of genetic abnormalities per tumor (NAPT) logged. The abnormalities present in more than 5% of tumors were considered recurrent and each karyotype was scored for the presence or absence of each of the recurrent abnormalities. To investigate the temporal pattern of acquisition of genetic abnormalities, all tumors with a given abnormality were selected and the distributions of NAPT plotted. The modes of these distributions were used as a value of ‘lateness’, referred to as time of occurrence (TO). The impact of co-existence of 13q- and t(14q32) on progression free survival (PFS) and overall survival (OS) in H-MM was determined for MM patients entered into an Eastern Cooperative Oncology Group chemotherapy trial. Four hundred and sixty-nine H-MM patients were included in the karyotypic analysis. The median chromosome number was 53 (range 48–74) and the median NAPT was 10 (range 1–25). The distribution of NAPT revealed a normal distribution, suggesting an obligatory acquisition of a given number of genetic abnormalities. The most common abnormalities were trisomies of chromosomes 3,5,7,9,11,15,19 and 21 affecting a third or more of the patients. Deletions and abnormalities of even-numbered chromosomes occur in 20% or less of patients. None of the more than 300 specific translocations detected were recurrent. However, 5 translocation breakpoints were recurrent including 14q32, 8q24 and 11q13. TO analysis suggest that for H-MM, the trisomies are early genetic events, translocations occur midway and deletions tend to be later events. Amongst the trisomies, correlation analysis does not suggest a particular order of acquisition. Clustering analysis using principal component analysis suggests that in H-MM, IgH translocations are secondary events associated with disease evolution rather than defining unique biological entities. Consistent with this, survival of H-MM patients is not affected by 13q- status but is negatively impacted by the presence of t(14q32) especially those with unknown partners (p<0.05). The data presented suggest that H-MM fit a proposed aneuploid model of cancer due to auto-catalytic chromosome reassortment (Duesberg et al Cell Cycle2003:2:202–210). The presence of tumor specific trisomies and the apparent similar phenotype induced by various combinations of trisomies are consistent with this model.

Abstract We investigated a new method using fluorescence in situ hybridization and DNA probes that span the common breakpoints of t(9;22)(q34;q11.2) and that detect double BCR/ABL fusion (D-FISH) in bone marrow cells with this translocation, one on the abnormal chromosome 9 and one on the Philadelphia chromosome (Ph chromosome). D-FISH patterns were abnormal in 30 of 30 specimens with classic, simple, complex, and masked Ph chromosomes. Based on 200 nuclei from each of 30 normal specimens, the mean percentage of false-positive cells was 0.25 ± 0.39. Thirty-seven specimens from 10 patients were studied before treatment and two or more times at 4-month intervals after treatment with interferon-α2b (IFN-α2b) with or without ara-C. Based on 200 nuclei, the results of D-FISH in these specimens correlated closely with quantitative cytogenetics and accurately quantified disease within a few percent. We studied 6,000 nuclei for each of six specimens, three normal and three from patients with chronic myeloid leukemia (CML) in cytogenetic remission. The normal cutoff for 6,000 nuclei was 0.079% and patients in cytogenetic remission had residual disease ranging from 7 (0.117%) to 53 (0.883%) Ph-positive nuclei. We conclude that D-FISH can detect the Ph chromosome and its variant translocations and accurately quantify disease in CML at diagnosis and at all times after treatment, including cytogenetic remission.

We investigated a new method using fluorescence in situ hybridization and DNA probes that span the common breakpoints of t(9;22)(q34;q11.2) and that detect double BCR/ABL fusion (D-FISH) in bone marrow cells with this translocation, one on the abnormal chromosome 9 and one on the Philadelphia chromosome (Ph chromosome). D-FISH patterns were abnormal in 30 of 30 specimens with classic, simple, complex, and masked Ph chromosomes. Based on 200 nuclei from each of 30 normal specimens, the mean percentage of false-positive cells was 0.25 ± 0.39. Thirty-seven specimens from 10 patients were studied before treatment and two or more times at 4-month intervals after treatment with interferon-α2b (IFN-α2b) with or without ara-C. Based on 200 nuclei, the results of D-FISH in these specimens correlated closely with quantitative cytogenetics and accurately quantified disease within a few percent. We studied 6,000 nuclei for each of six specimens, three normal and three from patients with chronic myeloid leukemia (CML) in cytogenetic remission. The normal cutoff for 6,000 nuclei was 0.079% and patients in cytogenetic remission had residual disease ranging from 7 (0.117%) to 53 (0.883%) Ph-positive nuclei. We conclude that D-FISH can detect the Ph chromosome and its variant translocations and accurately quantify disease in CML at diagnosis and at all times after treatment, including cytogenetic remission.

Abstract Pulmonary lymphangioleiomyomatosis (LAM) is an uncommon disease reported to occur exclusively in women. We describe a phenotypically normal man with pulmonary LAM. Fluorescence in situ hybridization (FISH) studies performed on the lung biopsy confirmed a normal XY genotype. Our patient also had stigmata of tuberous sclerosis complex (TSC), including facial angiofibromas and renal angiomyolipoma. Immunohistochemical stains of both LAM and renal angiomyolipoma showed positive immunoreactivity for hamartin (TSC1) and loss of immunoreactivity for tuberin (TSC2). Loss of heterozygosity (LOH) for TSC2 was further demonstrated in the renal angiomyolipoma. Coupled with the results of immunostains, these findings are consistent with TSC2 mutation.

Lymphoplasmacytic lymphoma (LPL) is characterized by t(9;14)(p13;q32) in 50% of patients who lack paraproteinemia. Waldenström macroglobulinemia (WM), which has an immunoglobulin M (IgM) paraproteinemia, is classified as an LPL. Rare reports have suggested that WM sometimes is associated with 14q23 translocations, deletions of 6q, and t(11;18)(q21;q21). We tested for these abnormalities in the clonal cells of WM patients. We selected patients with clinicopathologic diagnosis of WM (all had IgM levels greater than 1.5 g/dL). Southern blot assay was used to detect legitimate and illegitimate IgH switch rearrangements. In addition to conventional cytogenetic (CC) and multicolor metaphase fluorescence in situ hybridization (M-FISH) analyses, we used interphase FISH to screen for t(9;14)(p13;q32) and other IgH translocations, t(11;18)(q21;q21), and 6q21 deletions. Genomic stability was also assessed using chromosome enumeration probes for chromosomes 7, 9, 11, 12, 15, and 17 in 15 patients. There was no evidence of either legitimate or illegitimate IgH rearrangements by Southern blot assay (n = 12). CC (n = 37), M-FISH (n = 5), and interphase FISH (n = 42) failed to identify IgH or t(11;18) translocations. Although tumor cells from most patients were diploid for the chromosomes studied, deletions of 6q21 were observed in 42% of patients. In contrast to LPL tumors that are not associated with paraproteinemia and that have frequent t(9;14)(p13;q32) translocations, IgH translocations are not found in WM, a form of LPL tumor distinguished by IgM paraproteinemia. However, WM tumor cells, which appear to be diploid or near diploid, often have deletions of 6q21.

Primary systemic amyloidosis (AL) is a plasma cell (PC) dyscrasia with clinical similarities to multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS), but its molecular basis is poorly understood. Translocations at the immunoglobulin heavy-chain (IgH) locus, 14q32, are likely early genetic events in both MM and MGUS and involve several nonrandom, recurrent, partner chromosomes such as 11q13, 16q23, and 4p16.3. Given the similarities between MM, MGUS, and AL, bone marrow clonal PCs were evaluated in 29 patients with AL using interphase fluorescence in situ hybridization (FISH) combined with immunofluorescence detection of the cytoplasmic light-chain (cIg-FISH) for the presence of 14q32 translocations and the t(11;14)(q13;q32). Of 29 patients studied, 21 (72.4%) showed results compatible with the presence of a 14q32 translocation, and 16 (76.2%) of those had translocation (11;14)(q13;q32) for an overall prevalence of the abnormality of 55%. IgH translocations are common in AL, especially the t(11;14)(q13;q32).