Detection of trisomy 12 in chronic lymphocytic leukemia by fluorescence in situ hybridization to interphase cells: a simple and sensitive method

Abstract

Trisomy 12 is the most common cytogenetic abnormality in chronic lymphocytic leukemia (CLL), and a number of studies have suggested that it may be an adverse prognostic indicator. We have evaluated the usefulness of fluorescence in situ hybridization with a chromosome 12- specific probe as a simple means for detecting trisomy 12 in interphase cells. Forty cases of B-cell CLL previously studied with conventional cytogenetic techniques were analyzed with a biotinylated probe to the centromeric region of chromosome 12. Thirty of these retrospective cases could be reevaluated with in situ hybridization. Our analysis showed three hybridization signals (ie, trisomy 12) in interphase cells from seven of seven cases found previously to have trisomy 12. Trisomy 12 was also detected in five additional cases: in one case thought to have a normal karyotype, in two cases that had been inadequate for routine cytogenetic analysis, and in two cases that had been found to have an abnormal karyotype without trisomy 12. In a prospective series of 20 newly accrued CLL cases, all cases were analyzed successfully by in situ hybridization and six (30%) showed trisomy 12. We were able to perform the analysis on routinely prepared and previously Wright- stained peripheral blood smears. We conclude that fluorescence in situ hybridization is a simple means for the detection of trisomy 12 in CLL. The technique is more sensitive than conventional cytogenetic analysis and would be a useful tool in clinical studies.

Trisomy 8 in acute promyelocytic leukaemia: an interphase study by fluorescence in situ hybridization

“…Therefore, in agreement with previous studies (Losada et al, 1991;Anastasi et al, 1992;Cuneo et a?, 1992;Brizard et al, 1994: Flactif et aI, 1994Kwong et al, 1994), FISH has been demonstrated to be more sensitive than conventional cytogenetic analysis for numerical aberrations, particularly in minor clones. This is because FISH analyses more cells, and also cells which are quiescent and non-mitotic.…”

“…Recently, fluorescence in sftu hybridization (FISH) has been shown to be more sensitive than conventional cytogenetic analysis for detection of numerical chromosomal aberrations. These have included trisomy 12 in chronic lymphocytic leukaemia (Losada et al, 1991;Anastasi et al, 1992;Cuneo et al, 1992), and monosomy 7 in myeloid malignancies (Brizard et al, 1994: Flactif et al, 1994.…”

Genetic Features of B‐Cell Chronic Lymphocytic Leukemia

“…In all studies that compared conventional chromosome banding techniques and interphase cytogenetics, the frequency of trisomy 12 was higher when assessed by FISH using DNA probes that recognized the repetitive sequences of the cen-tromeric and pericentromeric region. The frequencies of trisomy 12 in the FISH studies range from 10 to 20% in most European series, to more than 30% in two studies from the United States (86,88). This variation possibly results from patient selection; however, differences may also be due to a different geographical distribution of this chromosome aberration.…”

“…Using restriction fragment length polymorphism (RFLP) studies, it was shown that trisomy 12 in CLL results from duplication of one homolog, rather than from loss of one homolog, and triplication of the remaining one (84). Trisomy 12 is the aberration most extensively studied by molecular cytogenetics in CLL (8,62,(85)(86)(87)(88)(89)(90)(91) (Table 1). In all studies that compared conventional chromosome banding techniques and interphase cytogenetics, the frequency of trisomy 12 was higher when assessed by FISH using DNA probes that recognized the repetitive sequences of the cen-tromeric and pericentromeric region.…”

Trisomy 12 in B‐cell chronic lymphocytic leukaemia: assessment of lineage restriction by simultaneous analysis of immunophenotype and genotype in interphase cells by fluorescence in situ hybridization

“…Chromosome abnormalities have been documented in 50% of cases (Oscier et al, 1988;Bird et al, 1989;Juliusson & Gahrton, 1990) with trisomy 12 being the most common aberration found as a single abnormality or in association with other chromosomal changes (Han et al, 1988;Geisler et al, 1989;Juliusson et al, 1990). The application of fluorescence in situ hybridization technique (FISH) to detect trisomy 12 in interphase nuclei has significantly increased the number of cases available for analysis (Anastasi et al, 1992;Cuneo et al, 1992;Dohner et al, 1993: Que et al, 1993. Although the significance of clonal chromosomal abnormalities in the pathogenesis of CLL is uncertain, trisomy 12 appears to correlate with atypical morphology and poor survival, and therefore it might be of prognostic importance (Juliusson et al, 1990(Juliusson et al, , 1991Que et al, 1993;Escudier et al, 1993).…”