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  • 1
    ISSN: 1432-0851
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary High-resolution two-dimensional polyacrylamide gel electrophoresis (PAGE) was employed to reveal tumor-associated polypeptide changes, using the BALB/c C4 line mouse mammary model system, for which phenotypic and immunogenic alterations accompanying tumor progression are well defined. In the first set of experiments, polypeptide patterns from 20 µg whole tissue lysates of normal mammary gland, C4 preneoplastic hyperplatic alveolar nodule outgrowth (HAN) and spontaneous tumor from C4 HAN were compared. In order to normalize for differential cellularity and extracellular protein content in the whole tissues, our analysis included polypeptide patterns from serum, increased concentration of protein from whole normal mammary gland, and primary cultures of epithelial cells from normal gland, HAN and tumor. Using a computer-based image-analysis system, 90 polypeptides were identified in C4 tumor that were absent in C4 HAN, normal mammary gland and serum. None of the 90 polypeptides could be shown to represent a definite qualitative change in the protein composition of tumor epithelium as they were found to be either present in a higher concentration of protein from whole normal gland, or present in the primary epithelial culture from HAN, or absent in the primary epithelial culture from tumor. Conversely in the second set of experiments, when epithelial cultures were used as the starting point for comparisons to locate tumor-associated polypeptides, none of the 15 polypeptides that were present in cultures from three different tumors, and absent in the culture from normal mammary gland was specific to C4 tumor, as they were present in whole tissues of normal gland. Thus our experimental approach detected significant quantitative but no qualitative polypeptide changes in whole tumor tissue, or in tumor-derived epithelial cell cultures. This finding may reflect the limitations of the two-dimensional PAGE method, and warrants caution in the use of such gel analysis alone to identify tumor-associated proteins.
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  • 2
    ISSN: 1573-7217
    Keywords: bilateral breast cancer ; genetic predisposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Our purpose was to determine whether bilateral breast cancer depends upon genetic predisposition to multiple tumors or, alternatively, represents two independent sporadic events. Biological concordance of hormone receptors and histopathology in bilateral tumors, family history of breast cancer, age at diagnosis, and survival were evaluated in 88 patients. The immunoreactivity of paired tumors from 51 patients to six different immunocytochemical markers was compared. Neither histologic patterns nor immunocytochemical reactions showed concordance between bilateral tumors. Absence of concordance (other than for estrogen receptors) and lack of associations with positive family history and early age of onset support an interpretation of independent tumor origins and does not suggest a major role for genetic determinants in the majority of cases of bilateral breast cancer.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-7217
    Keywords: breast cancer ; cell lines ; image analysis ; infiltrating ductal carcinoma ; polypeptides ; two-dimensional polyacrylamide gel electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The protein populations of epithelial cells cultured from two neoplastic and five non-neoplastic human breast tissues were resolved and displayed by two-dimensional polyacrylamide gel electrophoresis and silverstaining. With a computer-based image analysis system, we identified eight polypeptides which are present in both of the neoplastic cell lines, but absent from all five of the cultures of non-neoplastic breast cells. The eight polypeptides are not unique to cells cultured from neoplastic breast, because they are also found in cells cultured from non-breast tissues, both neoplastic and non-neoplastic. Two of the eight polypeptides (∼ Mr 25,000/pI 4.4 and ∼ Mr 31,000/pI 5.5) are present in the patterns of whole tissue samples from infiltrating ductal carcinomas and absent in most normal breast tissue.
    Type of Medium: Electronic Resource
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