Giovanna Venti

Expression of aphidicolin-induced fragile sites in lymphocytes of patients with breast cancer

The expression of fragile sites induced by aphidicolin (APC) was evaluated on metaphase chromosomes obtained from the peripheral blood lymphocytes of 26 women with breast cancer and 15 sex- and age-matched normal controls. Both the proportion of damaged cells (P < 0.001) and the mean number of gaps and breaks per cell (0.02 < P < 0.05) were significantly higher in the patient group. There were no differences in either the age-related fragile site levels or the expression of single fragile sites between patients and controls. Our findings indicate an increased genetic instability in women with breast carcinoma.

Glycosaminoglycan Metabolism and Cytokine Release in Normal and Otosclerotic Human Bone Cells Interleukin-1 Treated

Glycosaminoglycans (GAGs), normal components of the extracellular matrix (ECM), and the glycosidases, that degrade them, play a key role in the bone remodelling process. The effects of interleukin-1 alpha (IL-1 alpha) on GAG metabolism in normal and otosclerotic human bone cells as well as its capacity to modulate IL-1 alpha, IL-1 beta and IL-6 secretion in both populations was analyzed. The amount of radiolabeled GAGs was lower in otosclerotic than in normal bone cells. IL-1 alpha reduced newly synthesized cellular and extracellular GAGs in normal cells, but only those of the cellular compartment in otosclerotic bone cells. It depressed heparan sulphate (HS) more in normal cells and chondroitin sulphate (CS) more in otosclerotic bone cells. The HA/total sulphated GAG ratio was shifted in favour of the latter in otosclerotic cells, whereas the opposite effect was seen after IL-1 alpha treatment. There was little difference in the beta-D-glucuronidase levels of the normal and pathological cells, while beta-N-acetyl-D-glucosaminidase was significantly increased in otosclerotic bone cells. As the activity of neither enzyme was modified by treatment with IL-1 alpha, the cytokine seems to exert its influences on GAG synthesis rather than on the degradation process. IL-1 alpha, IL-1 beta and IL-6 secretion was markedly higher in otosclerotic cells. IL-1 alpha modulated the secretion of each interleukin differently, thus resulting in a cytokine cascade that may act in autocrine/paracrine manner on target cells. The authors suggest that changes in the cytokine network may have a specific, yet still unknown, role during normal and pathological osteogenesis.

Cytogenetic and molecular evaluation of 241 small supernumerary marker chromosomes: cooperative study of 19 Italian laboratories

Purpose: We evaluated the experiences of 19 Italian laboratories concerning 241 small supernumerary marker chromosomes (sSMCs) with the aim of answering questions arising from their origin from any chromosome, their variable size and genetic content, and their impact on the carriers phenotype.Methods: Conventional protocols were used to set up the cultures and chromosome preparations. Both commercial and homemade probes were used for the fluorescent in situ hybridization analyses.Results: A total of 113 of the 241 sSMCs were detected antenatally, and 128 were detected postnatally. There were 52 inherited and 172 de novo cases. Abnormal phenotype was present in 137 cases (57%), 38 of which were antenatally diagnosed. A mosaic condition was observed in 87 cases (36%). In terms of morphology, monocentric and dicentric bisatellited marker chromosomes were the most common, followed by monocentric rings and short-arm isochromosomes. The chromosomes generating the sSMCs were acrocentric in 132 cases (69%) and non-acrocentric chromosomes in 60 cases (31%); a neocentromere was hypothesized in three cases involving chromosomes 6, 8, and 15.Conclusion: The presented and published data still do not allow any definite conclusions to be drawn concerning karyotype–phenotype correlations. Only concerted efforts to characterize molecularly the sSMCs associated or not with a clinical phenotype can yield results suitable for addressing karyotype–phenotype correlations in support of genetic counseling.

Localization of the human HF.10 finger gene on a chromosome region (3p21–22) frequently deleted in human cancers

SummaryThe finger motif is a tandemly repeated DNA-binding domain recently identified in the primary structure of several eukaryotic transcriptional regulatory proteins. It has been proposed that some members of the finger-gene family are implicated in both normal cell proliferation and differentiation. We isolated several human finger genes by means of hybridization with a finger motif-containing DNA probe. One of these finger genes, HF.10, is expressed at low levels in a variety of human tissues and is down-regulated during the in vitro terminal differentiation of human leukemic myeloid cell lines. By in situ hybridization experiments and analysis of interspecific somatic cell hybrids we mapped the HF.10 gene to 3p21–22, a chromosome region frequently involved in karyotypic rearrangements associated with lung and renal cancer.

The constitutional fragility of chromosome 12 in a case of 46,XX,var(12)(qh′,RHG,GAG,CBG)

SummaryThe constitutional fragility of chromosome no. 12 in a female infant with unspecific clinical signs is described. RHG, GAG, and CBG methods were used to localize the fragile point. The breaks seem to be in 12q1.3, and always within an R band. A possible correlation between the phenotypic modifications and the chromosome variant is discussed.

Trisomy 6p22→6pter due to familial t(6;13)(p22;q34 or 33) translocation

SummaryA newborn with a 46,XY, der(13),t(6;13)(p22;q34 or 33)pat karyotype, trisomic for the 6p22→6pter segment and, perhaps, monosomic for the 13q telomere, is reported. The balanced translocation is familial and was also encountered in the sister and paternal grandmother. The infants phenotype was similar to that described in seven previously reported cases of partial trisomy 6p and further supports a partial trisomy 6p syndrome as proposed by Breuning et al.

Occurrence of the same chromosome abnormalities in Ph+ and Ph- cells in chronic myeloid leukaemia. Evidence of a secondary origin of the Ph chromosome?

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Acute myeloblastic leukemia after adjuvant chemotherapy with melphalan in breast cancer. Case report with cytogenetic analysis.

Therapy of solid and hematologic tumors with alkylating agents appears to increase the frequency of acute non-lymphocytic leukemia (ANLL), as indicated by the cases reported in the literature. The carcinogenetic mechanism of alkylating agents seems related to their ability to damage DNA, and this is supported by the findings of multiple cytogenetic abnormalities in these patients. We report a case of ANLL secondary to therapy with melphalan, which was utilized on an adjuvant basis for breast cancer. ANLL developed 24 months after chemotherapy was discontinued. Results of the cytogenetic analysis in our patient showed multiple rearrangements and marker chromosomes. Among these was a large metacentric chromosome, identified in 6 of 8 karyotypes, in the size range of group A, which probably resulted from a translocation t(7;14) (7qter→7p11::14p11-→14qter). The natural history of the underlying disease and of the ANLL in our patient and data from chromosomal analysis seem to confirm the hypothesis that alkylating agents are potentially leukemogenic in man, probably through genetic damage. This possibility should be considered when such cytotoxic drugs are used in an adjuvant setting.