Abstract
Amplification of mdr-1 occurs in breast cancer patients receiving endocrine treatment. We have compared a group of patients receiving tamoxifen and a group receiving second-line endocrine treatment after failure of tamoxifen treatment. Chronological tumor samples were obtained by fine-needle biopsies from the same tumor lesion of each patient and PCR was used to detect the appearance of gene amplification. Three of 20 patients receiving tamoxifen developed amplified mdr-1 whereas 7 of 17 patients receiving second-line endocrine treatment developed mdr-1 amplification.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP Binding Cassette Transporter, Subfamily B, Member 1
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Aged
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Aged, 80 and over
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Aminoglutethimide / administration & dosage
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Biopsy, Needle
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Breast Neoplasms / drug therapy
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Breast Neoplasms / genetics*
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DNA, Neoplasm / genetics
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Gene Amplification*
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Humans
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Membrane Glycoproteins / genetics*
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Middle Aged
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Progesterone / administration & dosage
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Tamoxifen / therapeutic use*
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Testosterone / administration & dosage
Substances
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ATP Binding Cassette Transporter, Subfamily B, Member 1
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DNA, Neoplasm
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Membrane Glycoproteins
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Tamoxifen
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Aminoglutethimide
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Testosterone
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Progesterone