Genomic imbalances in urothelial cancer: intratumor heterogeneity versus multifocality.

Comparative genomic hybridization and fluorescence in situ hybridization were used to define genetic changes associated with multifocal bladder cancer and to investigate whether the genetic relationship between synchronous urothelial tumors is similar to that observed within different parts of the same tumor. We investigated 8 synchronous urothelial tumors from 3 patients and macroscopically different parts of the same tumor from 2 other patients. The most frequent imbalances were gains of 1q, 2p, and 17q, and losses in 4q.

The importance of aneuploidy screening in reciprocal translocation carriers.

The purpose of this study is to investigate the aneuploidy rate and the mosaicism of chromosomes not involved in reciprocal translocations. Aneuploidy screening (AS) (13, 16, 18, 21 and 22) was performed as a re-analysis on fixed blastomeres from 126 embryos already analysed in preimplantation genetic diagnosis (PGD) cycles of eight female and five male reciprocal translocation carriers who had not achieved a pregnancy. A successful diagnosis for AS was achieved in 91.

Genetic reproductive risk in inversion carriers.

Objective: To evaluate the risk of four inversion carriers for producing unbalanced gametes.

Design: Prospective analysis of sperm nuclei by fluorescence in situ hybridization (FISH).

Setting: Universitat Autònoma de Barcelona.

Common pattern of unusual chromosome abnormalities in hereditary papillary renal carcinoma.

In this study, we summarized cytogenetic and comparative genomic hybridization (CGH) results, mutation analysis of the MET gene, and immunohistochemistry results of tumors from three patients in the same family who were affected by hereditary papillary renal carcinoma (HPRC). All three patients showed germline mutations in the tyrosine kinase domain of the MET proto-oncogene, and developed bilateral and multiple papillary renal tumors. DNA mutation analysis showed an increased dosage of the mutant allele in six tumors from two patients but not in two tumors from the third patient.

Genomic instability in rat: breakpoints induced by ionising radiation and interstitial telomeric-like sequences.

The Norwegian rat (Rattus norvegicus) is the most widely studied experimental species in biomedical research although little is known about its chromosomal structure. The characterisation of possible unstable regions of the karyotype of this species would contribute to the better understanding of its genomic architecture. The cytogenetic effects of ionising radiation have been widely used for the study of genomic instability, and the importance of interstitial telomeric-like sequences (ITSs) in instability of the genome has also been reported in previous studies in vertebrates.

Postreplicative joining of DNA double-strand breaks causes genomic instability in DNA-PKcs-deficient mouse embryonic fibroblasts.

Combined cytogenetic and biochemical approaches were used to investigate the contributions of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) in the maintenance of genomic stability in nonirradiated and irradiated primary mouse embryo fibroblasts (MEF). We show that telomere dysfunction contributes only marginally to genomic instability associated with DNA-PKcs deficiency in the absence of radiation. Following exposure to ionizing radiation, DNA-PKcs-/- MEFs are radiosensitized mainly as a result of the associated DNA double-strand break (DSB) repair defect.

Genome-wide differences between microsatellite stable and unstable colorectal tumors.

Genomic copy number changes are frequently found in cancers and they have been demonstrated to contribute to carcinogenesis; and it is widely accepted that tumors with microsatellite instability (MSI) are genetically stable and mostly diploid. In the present study we compared the copy number alterations and the gene-expression profiles of microsatellite stable (MSS) and MSI colorectal tumors. A total number of 31 fresh-frozen primary tumors (16 MSS and 15 MSI) were used.

FISH studies of chromosome abnormalities in germ cells and its relevance in reproductive counseling.

Chromosome abnormalities are one of the major causes of human infertility. In infertile males, abnormal karyotypes are more frequent than in the general population. Furthermore, meiotic disorders affecting the germ cell-line have been observed in men with normal somatic karyotypes consulting for infertility.

Telomere dysfunction drives chromosomal instability in human mammary epithelial cells.

The development of genomic instability is an important step toward generating the multiple genetic changes required for cancer. Telomere dysfunction is one of the factors that contribute to tumorigenesis. Telomeres shorten with each cell division in the absence of telomerase.

Synapsis and meiotic recombination analyses: MLH1 focus in the XY pair as an indicator.

Background: Anomalies in meiotic prophase I have been related to partial or total meiotic arrest. These anomalies include an abnormal synaptic process, resulting in disorders in meiotic recombination.

Methods: In the present study, we analyse primary spermatocytes from 12 infertile men (four with non-obstructive azoospermia, six with oligoastenoteratozoospermia, one with astenoteratozoospermia and one normozoospermic) and five control fertile donors using immunocytological techniques for synaptonemal complex, meiotic recombination and centromeric proteins.

Comprehensive measurement of chromosomal instability in cancer cells: combination of fluorescence in situ hybridization and cytokinesis-block micronucleus assay.

Most tumors show abnormal karyotypes involving either chromosome rearrangements and/or aneuploidies. The aim of our study is to measure the rate of both structural and numerical chromosome instability in two colorectal cancer cell lines: HCT116, and SW480 and its single subclones. To determine structural instability, we measured the nonclonal chromosome alterations of the last cell division by means of multicolor-fluorescence in situ hybridization (FISH).

Chromosomal instability in amniocytes from fetuses of mothers who smoke.

Context: Tobacco increases the risk of systemic diseases, and it has adverse effects on pregnancy. However, only indirect data have been published on a possible genotoxic effect on pregnancy in humans.

Objectives: To determine whether maternal smoking has a genotoxic effect on amniotic cells, expressed as an increased chromosomal instability, and to analyze whether any chromosomal regions are especially affected by exposure to tobacco.

Preferential alternate segregation in the common t(11;22)(q23;q11) reciprocal translocation: sperm FISH analysis in two brothers.

Segregation behaviour studies in t(11;22) carriers have reported controversial results. Whereas some authors have detected a preponderance of 3:1 products, no evidence of such prevalence was found by others. This study reports a fluorescence in-situ hybridization (FISH) segregation analysis on decondensed spermatozoa in two brothers, carriers of the same t(11;22)(q23;q11) rearrangement.

Capping of radiation-induced DNA breaks in mouse early embryos.

The aim of the study was to investigate the spectrum and frequencies of chromosome aberrations induced by the exposure of different mouse spermatogenic germ cell stages to ionizing radiation. Male mice were exposed in vivo to X-rays. Chromosome aberrations were analyzed in first- and second-embryonic cleavages obtained from mating irradiated males with nonirradiated females at different periods after radiation exposure.

Primary amenorrhea in a woman with a cryptic complex chromosome rearrangement involving the critical regions Xp11.2 and Xq24.

Objective: To characterize a complex chromosome rearrangement (CCR) previously detected by G-banding in peripheral blood lymphocytes, as 46,X,-2,-11,-22,-X,+mar 1+mar2+mar3+mar4 in a patient with primary amenorrhea.

Design: Case report.

Setting: University faculty of Medicine and hospital.

Conservation of aphidicolin-induced fragile sites in Papionini (Primates) species and humans.

Fragile sites are considered structural features of mammalian chromosomes and a commonly repeated hypothesis is that they are evolutionarily conserved. We tested this hypothesis by establishing the subchromosomal homology of regions harbouring fragile sites in the chromosomes of humans, Macaca fascicularis (MFA) and Mandrillus sphinx (MSP). We delineated the interspecific homology of chromosome bands expressing aphidicolin-induced fragile sites of homologues to human chromosomes 1, 3, 5, 7, 18 and X by the comparative FISH of human BAC and YAC clones.

Repair of DNA broken ends is similar in embryonic fibroblasts with and without telomerase.

Telomeres cap the ends of chromosomes, preventing end-to-end fusions and subsequent chromosome instability. Here we used a telomerase knockout model to investigate whether telomerase participates in the processes of DNA break repair by de novo synthesis of telomere repeats at broken chromosome ends (chromosome healing). Chromosome healing giving rise to new detectable telomeric signals has not been observed in embryonic fibroblasts of telomerase-proficient mice exposed to ionizing radiation.

Identification of meiotic anomalies with multiplex fluorescence in situ hybridization: Preliminary results.

Objective: To characterize meiotic anomalies in infertile men by multiplex fluorescence in situ hybridization (M-FISH) and to determine whether synaptic problems affect specific bivalents or whether anomalies are random.

Design: Analysis of meiotic preparations with standard techniques and M-FISH.

Setting: Assisted reproduction centers and Universitat Autònoma de Barcelona.

Reliability of comparative genomic hybridization to detect chromosome abnormalities in first polar bodies and metaphase II oocytes.

Background: Preimplantation Genetic Diagnosis (PGD) using FISH to analyze up to nine chromosomes to discard chromosomally abnormal embryos has resulted in an increase of pregnancy rates in certain groups of patients. However, the number of chromosomes that can be analyzed is a clear limitation. We evaluate the reliability of using comparative genomic hybridization (CGH) to detect the whole set of chromosomes, as an alternative to PGD using FISH.

Genetic evolution in colon cancer KM12 cells and metastatic derivates.

So far, CRC cell lines have contributed to descriptions of 2 patterns of genetic instability, affecting either microsatellite sequences or chromosome number and structure. Often, these patterns are mutually exclusive; while near-diploid karyotypes usually appear with MSI and chromosomal stability, near-triploid or tetraploid cells display a high degree of CIN and are stable at the microsatellite level. In the present study, we describe the genomic instability pattern of KM12 CRC cells.

Molecular cytogenetic characterisation of the colorectal cancer cell line SW480.

It has been demonstrated that 24-color FISH is not sufficient to understand completely the behaviour of chromosomal markers, especially in solid tumors. In the present study we show the usefulness of molecular cyto-genetic techniques, such as multicolour banding (MCB) and centromere-specific multicolour-FISH (cenM-FISH) performed on the colorectal cancer cell line SW480. Applying these approaches previously described chromosomal breakpoints could be redefined and six 'marker chromosomes' could be thoroughly characterised.

Karyotyping of human synaptonemal complexes by cenM-FISH.

The purpose of this work was to adapt the recently described centromere-specific multicolour (cenM-) FISH technique to human meiotic cells, and evaluate the usefulness of this multiplex fluorescence method for karyotyping human synaptonemal complex (SC), previously analysed by immunocytogenetic approaches. The results obtained demonstrate that cenM-FISH is a reliable one-single-step method, which allows for the identification of all SC present in pachytene spreads. Moreover, when cenM-FISH is applied after immunocytogenetic analysis, the number and distribution of MLH1 foci per chromosome can be established and recombination analysis for each chromosome can be performed easily.

Linear increase of structural and numerical chromosome 9 abnormalities in human sperm regarding age.

A simultaneous four-colour fluorescence in situ hybridisation (FISH) assay was used in human sperm in order to search for a paternal age effect on: (1) the incidence of structural aberrations and aneuploidy of chromosome 9, and (2) the sex ratio in both normal spermatozoa and spermatozoa with a numerical or structural abnormality of chromosome 9. The sperm samples were collected from 18 healthy donors, aged 24-74 years (mean 48.8 years old).

Outcome of intracytoplasmic sperm injection in relation to the meiotic pattern in patients with severe oligoasthenozoospermia.

Objective: The aim of the study was to evaluate the intracytoplasmic sperm injection outcome in a selected group of patients with oligoasthenozoospermia in relation to the results obtained from their meiotic analysis.

Design: Retrospective clinical study.

Setting: An assisted reproduction service and a university department.