Telomerase maintains ends of eukaryotic chromosomes, telomeres. Telomerase loss results in replicative senescence and a switch to recombination-dependent telomere maintenance. Telomerase insufficiency in humans leads to telomere syndromes associated with premature ageing and cancer predisposition. Here we use yeast to show that the survival of telomerase insufficiency differs from the survival ...

The many complex phenotypes of cancer have all been attributed to “somatic mutation.” These phenotypes include anaplasia, autonomous growth, metastasis, abnormal cell morphology, DNA indices ranging from 0.5 to over 2, clonal origin but unstable and non-clonal karyotypes and phenotypes, abnormal centrosome numbers, immortality in vitro and in transplantation, spontaneous progression of malignan...

BACKGROUND Human embryos produced by in vitro fertilization (IVF) are usually cultured to day 6 after insemination, and good quality of embryos should develop to blastocyst stage at days 5 and 6. However, some embryos develop slowly, thus they may form blastocysts on day 7. Most IVF laboratories culture embryos to day 6 and then discard retarded embryos that do not develop to blastocyst stage. ...

The relative contribution of aneuploidy and gene mutations to human tumorigenesis is not yet known. Studies in mice have demonstrated that even single point mutations in oncogenes and tumor suppressor genes can dramatically increase tumor frequency. However, models to evaluate the definitive role of aneuploidy and genomic instability are not yet available. Human fibroblast cells have long been ...

Aneuploidy-chromosome instability leading to incorrect chromosome number in dividing cells-can arise from defects in centrosome duplication, bipolar spindle formation, kinetochore-microtubule attachment, chromatid cohesion, mitotic checkpoint monitoring or cytokinesis. As most tumours show some degree of aneuploidy, mechanistic understanding of these pathways has been an intense area of researc...

BACKGROUND Maternal ageing is the only aetiological factor unequivocally linked to aneuploidy. Two mechanisms seem to explain these abnormalities in oocytes: non-disjunction and premature unbalanced separation of sister chromatids (PSSC). Previous studies of unfertilized oocytes argue for a major role of PSSC in the aetiology of aneuploidy for women of advanced age, but in vitro ageing of the o...

Aneuploidy, the unbalanced number of chromosomes in a cell, is considered a prevalent form of genetic instability and is largely acknowledged as a condition implicated in tumorigenesis. Epigenetic alterations like DNA hypomethylation have been correlated with cancer initiation/progression. Furthermore, a growing body of evidence suggests the involvement of epigenome-wide disruption as a cause o...

During a prospective study lasting 3.5 years flow cytometric DNA analysis was evaluated as a possible predictor of dysplastic and malignant lesions in longstanding ulcerative colitis. Fifty three patients with total ulcerative colitis (mean disease duration of 22 years) were regularly colonoscoped. Biopsies of colonic mucosa were analysed by flow cytometric technique and were also assessed hist...

Inactivation of the p53 gene, located on chromosome 17p, leads to genetic instability and aneuploidy in vitro. Aneuploid cell populations from Barrett's adenocarcinomas have a high prevalence of 17p allelic losses, and there is substantial evidence that the target of these losses is the p53 gene. If 17p allelic losses lead to aneuploidy in Barrett's esophagus, then they should be present in dip...

Most solid tumors contain aneuploid cells, indicating that the mitotic checkpoint is permissive to the proliferation of chromosomally aberrant cells. However, mutated or altered expression of mitotic checkpoint genes accounts for a minor proportion of human tumors. We describe a Drosophila melanogaster tumorigenesis model derived from knocking down spindle assembly checkpoint (SAC) genes and pr...