Aliza Amiel

Replication pattern of the p53 and 21q22 loci in the premalignant and malignant stages of carcinoma of the cervix

Loss of replication synchrony during the S‐phase of the cell cycle has been shown to be associated with aneuploidy in malignant cells.

Asynchronous replication of p53 and 21q22 loci in chronic lymphocytic leukemia.

Abstract In this study, in order to evaluate the replication pattern and the cell cycle dynamics of normal and malignant cells from patients with chronic lymphocytic leukemia, we applied the FISH technique with the p53 gene. Asynchrony was determined by the presence of one single and one set of double dots in the same cell. The rate of asynchronous replication was significantly higher in malignant cells than in normal cells (a mean of 28 vs 13, respectively, P = 0.023). There were proportionately more cells with two single dots among the normal cells (P = 0.0047). These results probably reflect the changes in gene replication and cell cycle progression that occur in malignant cells.

Replication status as a marker for predisposition for lymphoma in patients with chronic hepatitis C with and without cryoglobulinemia.

OBJECTIVEnEssential mixed cryoglobulinemia (EMC) type II is associated with hepatitis C virus (HCV) in 90% of the patients with this disorder. A significant subset of these patients is at risk to develop non-Hodgkin lymphoma (NHL). The objective of this study was to examine whether the presence of EMC, a presumably premalignant step of lymphoproliferation, is associated with changes in the replication state of normal structural genes.nnnMATERIALS AND METHODSnThe study group included three subgroups: (1) seven patients with HCV without EMC; (2) eight patients with HCV associated with EMC. 3. Seven patients with follicular lymphoma; and (3) six healthy individuals served as control group. Monocolor fluorescent in situ hybridization (FISH) with probes to p53, RB-1, and 21q22 was applied to leukocytes nuclei for the evaluation of replication timing.nnnRESULTSnAsynchronous replication (SD) rate was similar in patients with NHL and those with HCV associated with EMC and both are significantly higher when compared to patients with HCV without EMC and to normal controls (p < 0.01) for each comparison. This held true for all studied loci (21q22, RB-1, and p53). Patients infected by HCV (but without EMC) had a significantly higher rate of asynchronous pattern in comparison with healthy controls (p < 0.01).nnnCONCLUSIONSnPatients with a premalignant clinical condition HCV with EMC already demonstrate asynchronous type of replication which is similar to patients who already have an established malignant disease (i.e., NHL). In the future, replication may be used to assess the risk of malignant transformation in patients with benign proliferation.

Fluorescence in situ hybridization for the detection of trisomies 8 and 9 in polycythemia vera.

Trisomies 8 and 9 are the most common numerical chromosome abnormalities in polycythemia vera (PCV). Their role in the pathogenesis of the disease is unclear, however, as is their diagnostic or prognostic value. We evaluated fluorescent in situ hybridization as compared to chromosome analysis for the detection of trisomies 8 or 9 in peripheral blood cells of PCV patients. We demonstrated that FISH is a more sensitive method for the detection of the abnormalities. A positive correlation between the duration of the disease and trisomy 9 was found. FISH is a sensitive, convenient, and rapid method for the diagnosis and follow-up of chromosome aberrations in patients with PCV. The application of FISH to a larger cohort of patients may provide valuable information regarding the role of the chromosomal aberrations in the initiation and progression of this disease.

Clinical detection of BCR-ABL fusion by in situ hybridization in chronic myelogenous leukemia

We describe the use of the fluorescence in situ hybridization (FISH) technique to detect residual Philadelphia chromosome-positive (Ph+) cells in a patient with blastic phase chronic myelogenous leukemia (CML) after aggressive cytoreductive treatment. The analysis was made in interphase nuclei because of the very small number of recognizable metaphases in leukemic patients. FISH was a reliable tool for the detection of chromosome translocations in interphase nuclei as compared with conventional cytogenetic and polymerase chain reaction (PCR) techniques.

Ataxia-telangiectasia: a variant with altered in vitro phenotype of fibroblast cells

The clinical and cellular phenotype of ataxia telangiectasia (AT) has been extensively documented in numerous patients of different ethnic groups and is characterized by several specific laboratory hallmarks, such as chromosomal instability, profound radiosensitivity and radioresistant DNA synthesis. Several recent reports have, however, shown variations on this theme. This article describes 2 Turkish siblings with AT, who showed a typical but somewhat more prolonged clinical course of the disease and altered characteristics of fibroblast cells, compared to the classical AT cellular phenotype. Fibroblast strains derived from these patients showed a normal cellular life span, moderate degrees of chromosomal instability and sensitivity to the lethal effects of X-rays and neocarzinostatin, and lack of radioresistant DNA synthesis. A compilation of the literature on AT variants and AT-like syndromes shows that in addition to the internal variability of AT, this disease occupies a limited segment within a large spectrum of clinical and cellular features, which are common to a variety of syndromes. Each of these syndromes covers a different segment in this spectrum. The genetic basis of this family of disorders might be complex.

In situ hybridization: A simple and sensitive method for detection of trisomy 12 in chronic lymphocytic leukemia

Chromosome aberrations are detected in only 50% of patients with chronic lymphocytic leukemia (CLL), owing usually to the low mitotic rate exhibited by the neoplastic lymphocytes. Fluorescence in situ hybridization (FISH) is a simple method for identifying numerical abnormalities of the target chromosome in interphase nuclei. Therefore, we used the FISH procedure with chromosome 12-specific a-satellite probe to evaluate 19 patients with CLL. Trisomy 12 was detected in interphase cells of 12 patients (63%). Cytogenetic analysis, performed in nine patients, yielded trisomy 12 in four (44%). FISH detected three patients with trisomy 12 in whom conventional cytogenetic method yielded a normal karyotype. FISH is a simple, reliable, and sensitive method for detection of trisomy 12 in patients with CLL.

Deletion of 6q27 in Chronic Lymphocytic Leukemia and Multiple Myeloma Detected by Fluorescence In Situ Hybridization

Nonrandom deletions of the long arm of chromosome 6 (6q) are associated with various lymphoid malignancies. It has been suggested that deletions of 6q25-27, 6q21, and 6q23 typically occur in intermediate-grade, high-grade, and low-grade lymphomas, respectively. We used fluorescence in situ hybridization (FISH) to evaluate the occurrence of 6q27 deletion in chronic lymphatic leukemia (CLL) and multiple myeloma (MM). 6q27 deletion was detected in 21% of patients with CLL and in 28% of patients with MM. The percentage of cells containing deletions ranged between 25-49. Two patients with MM had progressive disease and the aberration was detected in both. We conclude that FISH is a sensitive method to detect 6q27 deletion in lymphoproliferative disorders. Also, this deletion is not specific to intermediate-grade lymphomas, but occurs also in CLL and MM.

Replication Pattern in Cancer: Asynchronous Replication in Multiple Myeloma and in Monoclonal Gammopathy

In this study we evaluated the replication pattern and cell-cycle dynamics of cells from patients considered to have a premalignant condition (monoclonal gammopathy, or MGUS) and patients with multiple myeloma (MM), as well as healthy controls. We applied the fluorescence in situ hybridization (FISH) technique with the TP53, RB-1 and 21q22 loci on the patients cells. Asynchrony was determined by the presence of one single and one set of double dots in the same cell. The rate of asynchronic replication was significantly higher in the cells from MM patients, with intermediate value in the cells from MGUS, while the lowest rate was in cells from controls. We suggest that these results may reflect the changes in gene replication and cell-cycle progression that occur in premalignant and malignant cells.

Analysis of chromosomal aberrations in large hepatocellular carcinomas by comparative genomic hybridization

Hepatocellular carcinoma (HCC) is a very common and highly malignant tumor, associated mainly with chronic viral hepatitis, cirrhosis of any cause, aflatoxin exposure and ethanol consumption. The aim of this study was to map genomic aberrations in HCC by a recently developed technique: comparative genomic hybridization (CGH). We applied CGH on 17 liver specimens, of which seven were HCCs. The rest were benign liver tumors, cirrhotic and normal livers, and other liver malignancies. Our study included mainly large tumors (mean size 10.5 cm) unrelated to viral hepatitis or cirrhosis. Our CGH analysis detected genomic imbalances in 42% of HCCs. The common aberrations included DNA gains of 1q, 9p, and 8q and DNA losses of 17p, 13q, 9q, 4q, and 11q. Also, we detected trisomies 8, 9, 18 and 21, which have not been reported previously. Gains and losses of DNA found in this study probably involve oncogenes and tumor suppressor genes that play a role in the puzzle of hepatocarcinogenesis. This study also suggests a possible link between the size of the tumor and the burden of genetic changes.