Nakagawa H

Assignment of the human cytochrome P-450 nifedipine oxidase gene (CYP3A4) to chromosome 7 at band q22.1 by fluorescence in situ hybridization

SummaryWe have used a full length cDNA clone (2.2 kb) for the human cytochrome P-450 nifedipine oxidase (CYP3A4) enzyme as a probe to determine its chromosome localization by fluorescence in situ hybridization. CYP3A4 was mapped on R-banded human prometaphase chromosomes, and the precise localization of CYP3A4 on chromosome 7 was further confirmed by a delineation of G-banded pattern on the same prometaphase chromosomes through a combination of UV-filter. We assigned CYP3A4 to chromosome 7 at q22.1.

Reciprocal t(14;19)(q32.3;q13.1) in a patient with B-cell lymphoma

A patient with B-cell lymphoma with a chromosome rearrangement of t(14;19)(q32.3;q13.1) is reported. This patient had leukemic features and an aggressive clinical course. The histopathologic diagnosis was malignant lymphoma, small noncleaved cell. Chromosome analysis of the cells from a cervical lymph node and peripheral blood showed a reciprocal translocation between chromosome 14 with a break at band q32.3 and chromosome 19 with a break at band q13.1, to which the bcl-3 gene has been mapped. Monoclonal rearrangement of the JH gene was detected by Southern blot analysis. However, we could not detect rearrangement of the bcl-3 gene. This case also had a t(2;8)(q13;q24.1), but the c-myc gene remained in its germline. This is the first case with the reciprocal t(14;19) and 8q24 chromosomal breakpoint in a B-cell lymphoid malignancy.

Detection of an i(17q) chromosome by fluorescent in situ hybridization with a chromosome 17 alpha satellite DNA probe

An isochromosome for the long arm of chromosome 17,i(17q), is frequently found as an additional chromosome aberration to the Ph with advanced disease in the chronic myelocytic leukemia (CML). We studied an i(17q) in blood samples from two patients with CML in blast crisis with a biotinylated chromosome 17 specific alpha satellite deoxyribonucleic acid probe. G-banded karyotypes of these patients showed a dicentric i(17q), dic(17)(p11.2). Fluorescence in situ hybridization (FISH) delineated one normal chromosome 17 and one i(17q) among metaphase chromosomes; the latter showed a dicentric pattern. In most interphase nuclei of both patients, two fluorescence spots were observed. In some interphase nuclei, including mature neutrophils, the dicentric chromosome was discernible by its size and shape of the fluorescent spots. Three fluorescent spots were observed in a small proportion of interphase cells, and existence of a subclone with two normal chromosome 17 and an i(17q) was confirmed by examining a large number of metaphase plates. The results of FISH provided us with information of numerical and structural aberrations of chromosome 17 in interphase cells.

Detection of monosomy 7 by fluorescence in situ hybridization in acute nonlymphocytic leukemia and myelodysplastic syndrome.

SummaryFluorescence in situ hybridization (FISH) with a chromosome 7 specific alpha satellite DNA probe was used to detect monosomy 7 in interphase and metaphase cells obtained from patients with myelodysplastic syndrome (MDS) and acute nonlymphocytic leukemia (ANLL). Chromosome analysis revealed monosomy 7, either alone or as part of a complex chromosome abnormality, in all cell samples. FISH analyses of 12 marrow samples and a blood sample using a chromosome 7 specific alpha satellite DNA probe revealed a single fluorescence spot in 80.5–97.5% of interphase cells indicating monosomy 7. In contrast, 83.5–92.0% of the same cells had two copies of chromosome 17 as two fluorescent spots were detected using a chromosome 17 specific alpha satellite DNA probe used as a positive control. The proportion of interphase cells with monosomy 7 did not correlated with the percentage of metaphase cells with monosomy 7 detected by conventional karyotyping or with the percentage of blast cells in the bone marrow.

Regional chromosomal assignment of carcinoembryonic antigen gene (CEA) to chromosome 19 at band q13.2

Carcinoembryonic antigen (CEA), a glycoprotein, is one of the most widely used human tumor markers. It is a member of a gene family comprising about 10 closely related genes and might be found throughout mammalians. Recently, two parts of a genomic DNA for CEA were isolated and sequenced. Using these genomic DNA fragments as probes we assigned the human CEA gene to chromosome 19 at the band q13.2 by in situ hybridization.