ABCB1 1 ABCB1 gene Adult 1 Aged 1 Antineoplastic Agents, Hormonal 1 Breast Neoplasms 1 CYP2D6 1 Cytochrome P-450 CYP2D6 1 DNA polymorphism 1 Drug Resistance, Neoplasm 1 Female 1 Genotype 1 Humans 1 Kaplan-Meier Estimate 1 Middle Aged 1 Neoplasm Recurrence, Local 1 P-Glycoprotein 1 Polymorphism, Genetic 1 Tamoxifen 1 Time Factors 1 adult 1 aged 1 article 1 breast cancer 1 breast carcinogenesis 1 cancer recurrence 1 cancer relapse 1 cancer risk 1 cancer survival 1 controlled study 1