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Reduced occurrence of mdr ‐1 amplification in stage‐IV breast‐cancer patients treated with tamoxifen compared with other endocrine treatments
Author(s) -
Lönn Ulf,
Lönn Sigrid,
Stenkvist Björn
Publication year - 1993
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910530408
Subject(s) - tamoxifen , endocrine system , medicine , breast cancer , oncology , cancer , stage (stratigraphy) , hormone , biology , paleontology
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.