text_1: The relationship between a breast cancer patient's capacity to metabolize tamoxifen and treatment outcome is independent of the patient's genetic make-up.
text_2: CONCLUSION Among women with breast cancer treated with tamoxifen, there was an association between CYP2D6 variation and clinical outcomes, such that the presence of 2 functional CYP2D6 alleles was associated with better clinical outcomes and the presence of nonfunctional or reduced-function alleles with worse outcomes.