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  • 1
    ISSN: 1573-7217
    Keywords: breast cancer ; in situ hybridization ; interphase cytogenetics ; paraffin-embedded sections ; multistep carcinogenesis ; tumor cytogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fluorescentin situ hybridization techniques have provided an important tool for interphase cytogenetic studies of human neoplasms. However, these techniques are difficult to use on formalin-fixed archival tissue sections. We describe here a non-fluorescent, non-isotopicin situ hybridization (ISH) approach that is easily applicable to paraffin-embedded breast tissue sections. The technical steps that must be monitored and individualized to optimize signal generation and detection are discussed. This ISH technique has several advantages over fluorescent detection methods. The signal obtained can be viewed using an ordinary light microscope and does not fade with time. More importantly, the signal is observed and analyzed in the context of tissue morphology. The technique permits detection of numerical chromosomal abnormalities not only in malignant but also in apparently normal and potentially premalignant mammary tissue. This may allow identification of focal genetic abnormalities as well as field-defects and enable analysis of their evolution during the multistep transformation to mammary neoplasm. This technique is also suitable for analysis of tumor heterogeneity and the correlation of numerical chromosomal aberrations with histologic, immunocytochemical, and clinical features of breast tumors.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0730-2312
    Keywords: Breast cancer ; chemoprevention ; genetic instability ; intermediate biomarkers ; multistep carcinogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Current chemoprevention trial designs based on epidemiological risk assessment and occurrence of cancer as an endpoint are inefficient and expensive. Novel biomarkers are needed to facilitate the development of chemopreventive interventions. The following four categories of biomarkers may be useful in prevention trials: histologic and morphometric markers; phenotypic markers of dysregulated proliferation, differentiation, and cell loss; specific oncogenes and growth regulators which are qualitatively or quantitatively altered in breast cancers; and markers of genetic and epigenetic instability. Some of these markers will be generally useful regardless of the chemopreventive approach used, whereas others may be uniquely useful in trials of specific chemopreventive agents [e.g., upregulation of progesterone receptor (PR) expression in response to tamoxifen]. The development of these markers requires three phases of study: “Phase I”: assessing the prevalence of the putative marker in malignant and premalignant tissue from individuals who have developed breast cancer; “Phase II”: assessing in vivo modulation of the biomarker by the proposed chemopreventive agent; and “Phase III”: applying the proposed biomarker in larger-scale trials of chemopreventive agent in high-risk populations, either before or after the development of a primary breast malignancy. The use of these biomarkers may also allow identification of novel targets for chemoprevention.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 53 (1993), S. 233-236 
    ISSN: 0730-2312
    Keywords: head and neck cancer ; leukoplakia ; in situ hybridization ; field cancerization ; multistep carcinogenesis ; polysomy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Upper aerodigestive tract tumorigenesis has been hypothesized to represent a field cancerization process with multistep events based on its association with known carcinogens, its frequent associated premalignant lesions, and its multifocal clinical manifestation. To further explore this working hypothesis, we have examined normal tissue and premalignant lesions in the field of tumors for evidence of genetic change. Paraffin sections of head and neck tumors harboring neighboring premalignant lesions were explored for the presence of chromosome polysomies using in situ hybridization and chromosome-specific centromeric probes. Cell exhibiting random polysomy were observed in the premalignant regions near the tumors. The frequency of polysomy in the tumor field increased as the tissue progressed from normal morphology (33%), to hyperplasia (67%), to dysplasia (95%), and to squamous cell carcinoma (96%). These results support the notions of field cancerization and multistep tumorigenesis in the aerodigestive tract. To determine whether the degree of accumulated genetic alterations might serve as a biomarker for risk of developing malignancy, a set of biopsies of oral premalignant lesions (leukoplakia, erythroplakia) were retrospectively chosen for polysomy analysis from two groups of individuals: one group who subsequently developed oral cancer and one group who did not develop oral cancer. Three of the five individuals who showed significant chromosome polysomies in their biopsies subsequently developed oral cancer, whereas only one of eight individuals with little evidence of polysomy subsequently progressed to oral cancer. These results suggest that evidence of generalized genetic change or instability might be useful as a genetic biomarker for risk assessment.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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