Chromosome findings in multiple myeloma.

Cytogenetic studies were performed on six patients with multiple myeloma in which G-banding allowed the identification of clonal chromosome abnormalities. Normal cells and random chromosome gains and losses were seen in all cases. Numerical clonal aberrations were observed in two cases. Among the remaining cases, clonal chromosome rearrangements were seen in two cases, whereas, the other two patients revealed both numerical and structural clonal anomalies. The following marker chromosomes were identified: 1q-, 2p+, 2q+, 7q-, 17p-, and five unidentified abnormal chromosomes.

Translocation t(1;5) in a case of carcinoma of the cervix.

We report a case of carcinoma of the cervix uteri, which presented both numerical and structural chromosome changes. The tumor showed the coexistence of lines with different modal chromosome numbers, but all of them with the t(1;5)(q25;132). We also observed the presence of double minutes, dicentric chromosomes, small acentric fragments, and/or tri- and quadriradial figures in 11% of the cells.

Sister chromatid exchanges in leukemic patients.

Sister chromatid exchange (SCE) was studied in PHA-stimulated peripheral blood lymphocytes from 36 newly diagnosed and untreated leukemic patients: 16 with acute lymphoblastic leukemia (ALL), 10 with acute nonlymphocytic leukemia (ANLL), and 10 with chronic myelocytic leukemia (CML). The metaphases analyzed show no chromosomal abnormalities. The mean SCE frequency (mean +/- SE) for each group of patients was: 6.8 +/- 0.4, 6.6 +/- 0.3, and 7.0 +/- 0.6 per mitosis, respectively, which was significantly lower than the mean SCE score for 30 controls (8.7 +/- 0.2). No differences in SCE score among ALL, ANLL, and CML and a similar SCE frequency by chromosome number and group allowed consolidation of all the cases into a single group of 36 leukemic patients (6.8 +/- 0.3). When the frequency of SCE was compared by chromosome number and group between the leukemic patients with the control group, a significant decrease in SCE frequency was observed due to a low SCE score in almost all the complements, except chromosome #1. It is suggested that the low SCE rate is related to the leukemic process itself.

Heterochromatic variants and their association with neoplasias. II. Preleukemic states.

A study of the heteromorphism of chromosomes #1, #9, and #16 was performed in the cells of 55 normal subjects and in those of 40 preleukemic patients including those with refractory anemia (RA) and sideroblastic anemia (SA), classified on the basis of the FAB nomenclature. Heteromorphism was present in 85% of the preleukemic patients, compared with 44% in normal controls (p less than 0.01). The patient population presented an increased incidence of C-band size variants in chromosome #1 (1qh+ and 1qh-), while chromosomes #9 and #16 showed no difference, compared with the findings in the control group.

Heterochromatic variants and their association with neoplasias. I. Chronic and acute leukemia.

C-banding studies of the heteromorphism of chromosomes #1, #9, and #16 were performed in 120 leukemic patients: 56 with chronic myelocytic leukemia (CML), 45 with acute lymphoblastic leukemia (ALL), and 19 with acute nonlymphoblastic leukemia (ANLL). No differences were found among patients and controls with regard to sex. Our data showed a significant increase of polymorphism in chromosome #1 in the three neoplastic groups; the heterochromatic variant preferentially involved 1qh-, whereas there were no significant differences in heteromorphism in chromosomes #9 and #16.

In vivo and in vitro cytogenetic effects of the anti-tumor agent amsacrina (AMSA).

The genotoxic effect of AMSA, an anti-tumor agent, was evaluated using the micronucleus and anaphase-telophase tests. The doses assayed by the in vivo micronucleus test were 1.5, 3 and 6 mg/kg: they are within the range of those used in clinical trials. A significant increase of micronucleated cells (P less than 0.01) was observed in the three assayed doses, with a linear dose response (r 0.98). In the in vitro test, 3 drug concentrations, i.e. 10, 1 and 0.1 microgram/ml, were analyzed with the 2 higher doses. AMSA showed a marked inhibition of cellular replication, but with 0.1 microgram/ml it was possible to determine an increase (P less than 0.01) in aberrations in anaphase-telophase cells. Both studies clearly demonstrate the clastogenic effect of the drug, which should be taken into account when considering its carcinogenic risk.

[Cytogenetic study of the Argentine "Cai" (Cebus apella)]. / Etude cytogénétique du "Cai" d'Argentine (Cebus apella).

The karyotype of the Argentine "Cai" (Cebus apella) is studied by different banding techniques (C and G). The analysis takes into account the results obtained from 15 specimens according to their geographic habitat. Comparative studies between phenotypic and karyotypic features suggest a phenotypic sub-speciation instead of a chromosomal. This proposition is supported by the observed karyologic stability. According to this report the genus Cebus and the species apella remains controversial from the systematic point of view.

Homogeneously staining regions (HSR) in a human malignant melanoma.

A case of nodular malignant melanoma (level V of Clark's classification) with homogeneously staining regions (HSR) on the long arm of one chromosome #2 is described. Ultrastructural observation of melanosomic and promelanosomic granules near Golgi's vesicles confirmed the histologic diagnosis. Chromosome analysis was performed on nine metaphases from a bone marrow sample and 76 metaphases from culture of the malignant skin tumor. G-banding revealed the presence of a clone with trisomy #8 and another cell line with the HSR marker. This is the first report of HSR in human melanoma cells. As HSR has been found only in malignant cells, we believe that among the many factors that influence the patients' clinical evolution and poor response to treatment, the genic imbalance is of the utmost importance.