Cytogenetic and molecular studies of Down syndrome individuals with leukemia

There is an increased risk of leukemia in Down syndrome (DS) patients, with estimates ranging from 14 to 30 times the incidence rate observed for chromosomally normal children. Furthermore, one type of leukemia, called "transient leukemia" (TL), occurs almost exclusively in DS infants. The basis of the association between DS and leukemia is unknown, but we and others have hypothesized that it may be influenced by the mechanism of origin of the extra chromosome. Therefore, we initiated a cytogenetic and molecular study of nondisjunction in leukemia DS individuals. To date, we have obtained blood and/or tissue samples from 55 individuals consisting of 17 cases with TL, 7 cases of acute nonlymphocytic leukemia subtype M7 (ANLL-M7, or acute megakaryoblastic leukemia, postulated to be related to TL), and 31 cases of other forms of leukemia. Analysis of these cases suggests differences between DS children with TL and those with other types of leukemia or DS individuals with no history of leukemia. Specifically, the TL and ANLL-M7 cases have a highly significant increase in the frequency of "atypical" constitutional karyotypes (i.e., mosaic trisomies, rings, and/or isochromosomes) and are almost always male. Additionally, genetic mapping studies suggest an increase in the frequency of disomic homozygosity, especially in proximal 21q, in DS individuals with TL and ANLL-M7.

Trisomy 2 and 20 in two hepatoblastomas

Cytogenetic analysis of two pediatric hepatoblastomas is presented, comparing results in primary tumor samples, nude mouse xenographs, and lung metastases in one case. Both tumors had trisomy 2 and 20 in the primary tumors, along with other structural abnormalities. In subsequent passages/metastases, both tumors showed structural changes in one chromosome 2, resulting in partial trisomy 2q, along with structural changes of other chromosomes. Partial trisomy 1q was also common to both tumors in late stages. Results are compared to those of embryonal rhabdomyosarcoma, where trisomy 2 has also been noted.

A familial MCA/MR syndrome due to translocation t(10;16) (q26;p13.1): report of six cases

A minute familial translocation t(10;16) (q26;p13.1) was detected in a family with 6 affected children in 2 generations and 9 carriers in 3 generations. This apparently unique translocation is associated with a deleterious syndrome which includes fetal hydrops, ascites, complex congenital heart defect, psychomotor retardation, failure to thrive, hypotonia, narrow palpebral fissures, abnormally modeled, apparently low-set ears, cleft palate, thumb abnormalities, hypogenitalism, inguinal hernia, and sparse hair. All children of known or presumed carriers have been either balanced or unbalanced carriers of this translocation.

Continuous human glioma-derived cell lines UC-11MG and UC-302MG. Morphologic, immunocytochemical and chromosomal characterization

Two continuous human glioma-derived cell lines, UC-11MG and UC-302MG were established in our laboratory. Both cell lines persistently showed cytologic features similar to those of their respective original tumors. UC-11MG expressed glial fibrillary acidic protein (GFAP) and S-100 protein. The cell lines were negative for factor VIII related antigen (FVIII/RAg) and positive for fibronectin and neuronal specific enolase (NSE). Electron microscopic studies of UC-11MG revealed intermediate filament; filopodia and pinocytic vesicles were present in both lines. Dibutyryl cAMP (dB-cAMP) caused inhibition of growth and marked shift in the morphology of UC-302MG toward spindle cells. The cytologic appearance of UC-11MG treated with dB-cAMP was altered less, but cells showed a stronger GFAP expression, with 'cable' formation. Doubling time was 41.0 +/- 6.4 hours for UC-11MG and 43.7 +/- 6.6 hours for UC-302MG. The karyotypes of both cell lines were aneuploid with chromosomal derangement and markers characteristic for each line.

Biologic characteristics of four Ewing's sarcomas

Four Ewing's sarcomas were examined for chromosomal characteristics, growth in cell culture, tumorigenicity in nude mice, and presence of beta-adrenergic receptors. Three tumors were from untreated patients (one obtained directly from the patient and two after growth in nude mice) and one was a metastatic lesion obtained after treatment. All four tumors were diploid or near-diploid, with one or more structural rearrangements. In the metastatic lesion, 21 abnormalities were seen. No specific chromosome aberration was found to be common to all four tumors, although a t(1,16) was observed in two and a t(11;22) in two. Abnormalities involving chromosomes #1, #3, #11, #13, #16, and #22 were each found in two of four tumors. All four tumors were tumorigenic in nude mice; two grew well in cell culture, one of which became an established line, and all four expressed high concentrations of beta-adrenergic receptors.

Chromosome features of two retinoblastomas

Giemsa-banded chromosomal analysis of two unilateral retinoblastoma tumors from unrelated patients with normal constitutional chromosomes revealed near-diploid karyotypes with multiple structural rearrangements. The two tumors shared aberrations of trisomy 1q, monosomy 16 and 17, and 21p+. Other aberrations were unique to each tumor. One tumor expressed a del(13) and trisomy 6p.

Clonal sublines of rat neurotumor RT4 and cell differentiation. VI. Chromosome analysis

The RT4 neurotumor cell system consists of clonally derived cell lines where a stem cell type segregates in vitro into three biochemically and morphologically different cell types, one glial and two neuronal types. This process has been termed cell-type conversion (M. Imada and N. Sueoka, 1978, Dev. Biol. 66, 97-108). Detailed cytogenetic analysis of the RT4 cell lines are described. Giemsa-banding analysis of 12 independent clonal isolates of the four different RT4 cell types showed a relatively stable karyotype. The stem cell line, RT4-AC, is diploid and most stable, and it has one 4q+ marker chromosome in place of a normal No. 4. This 4q+ marker was identified in all cell types of the RT4 system and was not observed in other cell lines of BDIX origin. The 4q+, therefore, is a chromosomal marker of the RT4 system. Consistent chromosome rearrangement was not found in any one of the cell-type conversions of the RT4-AC cells into the three derivative cell types. The relative stability of the karyotype of the different clonal isolates gives the RT4 system an advantage in studies of genetic regulation and expression of cell-type conversion in vitro. Also the 4q+ marker can be used to identify RT4 cells in coculture experiments or to distinguish RT4 cells in cases of suspected cell-line contamination.

Association of chromosome 4 abnormalities with ethylnitrosourea-induced neuro-oncogenesis in the rat

Cytogenetic studies of rat neurogenic tumor lines induced by ethylnitrosourea (ENU) have shown specific involvement of chromosome 4. The study reported here further characterizes the association of chromosome 4 abnormalities in rat tumor cell lines with regard to etiological agent, tissue of origin, and tumorigenic potential of cloned lines. Lines from rat gliomas induced by avian sarcoma virus did not show abnormalities of chromosome 4. ENU-induced rat tumors of nonneurogenic origin had numerical and/or structural abnormalities of chromosome 4 in seven of nine cell lines. In a comparison of two tumorigenic and two nontumorigenic cloned cell types from the same ENU-induced rat neural tumor, all showed excess chromosome 4. In addition, preneoplastic nervous system tissue, exposed to ENU in vivo, was cultured and sequentially monitored for the concurrent development of chromosome abnormalities and neoplastic properties. Abnormalities of chromosome 4 were observed in 3 of 14 tumorigenic lines and one nontumorigenic clone. The remaining lines had normal karyotypes or abnormalities involving chromosomes other than chromosome 4. Our results suggest that chromosome 4 abnormalities appear late in tumor development, are probably secondary to the tumorigenic potential of the studied cell lines, and apparently are not tissue specific. However, abnormalities of chromosome 4 may be associated preferentially with ENU oncogenesis.

Studies of cytogenetic effects of sodium arsenicals on mammalian cells in vitro

The cytotoxic and cytogenetic effect of sodium arsenite and sodium arsenate on Chinese hamster ovary (CHO) cells is reported. Chromosome aberrations were induced with both arsenic compounds. Trivalent arsenic was more clastogenic than pentavalent arsenic. Sodium arsenite was also shown to produce increased sister chromatid exchange in CHO cells and increased chromosome breakage in human lymphocytes.

Chromosome studies in a case of monoblastic leukemia

Chromosome analysis of a direct bone marrow preparation from a patient with acute, undifferentiated monoblastic leukemia showed a predominant clone of 51,XX,+6,+8,+4,+19,+21,11q+, along with a chromosomally normal clone. Studies with cytofluorometry confirmed the two populations of cells with different DNA content.

Chromosome analysis of a human neuroblastoma

Samplings of tumor cells from a patient with Stage IV neuroblastoma were analyzed for chromosome constitution. Chromosome preparations of the tumor cells from a bone marrow sample were compared to preparations of a solid metastatic tumor after growth in the nude mouse host or followed by culture. Six separate chromosome studies were done. The tumor karyotype demonstrated an overall stability, maintaining the consistent abnormalities of a 1p-, +17, and -22. Chromosomes 5 and 9 were also involved in structural abnormalities in sublines of the tumor cells. Double minutes were seen in all preparations.

Excess chromosome no. 4 in ethylnitrosourea-induced neurogenic tumor lines of the rat

The chromosomes in 15 cell lines derived from separate tumors induced in rats by ethylnitrosourea (ENU) are described. Thirteen lines were neural (glioma or schwannoma) in origin and type. In 12 of these lines, excess chromosome no. 4 could be demonstrated by Giemsa banding. One to three extra no. 4 chromosomes were seen as numerical or structural abnormalities. Also noted were other changes that were not consistent among lines. The 12 lines produced tumors in newborn rats. The 13th neurogenic line lacked excess chromosome no. 4 and did not produce tumors. The remaining 2 lines were nonneurogenic and lacked excess chromosome no. 4 but produced tumors. Control studies included chromosome analyses of bone marrow preparations from ENU-treated rats with tumors, cell lines from brains of normal rat embryos, and 2 established nonneurogenic rat tumor lines. No excess chromosome no. 4 was seen. These results suggest that nondisjunction and/or rearrangement of chromosome no. 4 is associated with the oncogenic process in neurogenic tumors induced.

Establishment of a human medulloblastoma cell line

A cell line consisting of polygonal and fusiform cells was derived from a cerebellar medulloblastoma. Cells grew to high population density in liquid medium and formed colonies in agar medium. No neural or glial elements could be demonstrated in the cultured cells by electron microscopy nor were virus particles detected. The cells formed tumors in nude mice and in antithymocytic serum (ATS)-treated hamsters. The tumors had a microscopic appearance similar to that of the medulloblastoma from which the cell line was derived. The cell line and lines derived from the transplant tumors in two hosts had four common "marker" chromosomes as well as non-specific cytogenetic changes.

Cat eye syndrome. Partial trisomy 22 due to translocation in the mother

We describe a case of cat eye syndrome with 47,XX, +22q--. A balanced translocation, 46,XX,t(11;22), was found by banding studies in the mother. The clinical and cytogenetic correlations disclosed by a review of sporadic and familial cases illustrate the heterogeneity of the syndrome and the challenge to genetic counseling.

The effect of ethylnitrosourea on chromosome aberrations in vitro and in vivo

The effect of ENU on (A) human chromosomes from blood lymphocyte cultures in vitro, and on (B) rat and mouse bone marrow chromosomes in vivo, was investigated. Doses of 25, 50, 100 and 200 mug/ml were tested in vitro and cells with chromosome breakage were found to be dose dependent. Chromosome damage was also dependent on time; maximum damage was seen when cells were treated 2--6 hrs before harvest. Two doses of 100 and 200 mg/kg were studied in rat and mouse in vivo and a dose effect could be shown in both species. The highest number of abnormal cells was found 6 hrs after treatment; there was a sharp decrease at 18 hrs and thereafer. Types of aberrations were also analyzed, in both in vitro and in vivo studies.