ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism; ATP-Binding Cassette Transporters/metabolism; Antineoplastic Agents, Phytogenic/therapeutic use; Breast Neoplasms/drug therapy; Catechin/analogs & derivatives; Neoplasm Proteins/metabolism; Plant Extracts/therapeutic use; ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters/genetics; Antineoplastic Agents, Phytogenic/pharmacology; Apoptosis/drug effects; Breast Neoplasms/genetics; Breast Neoplasms/metabolism; Camellia sinensis/chemistry; Catechin/pharmacology; Catechin/therapeutic use; Cell Line, Tumor; Cell Proliferation/drug effects; Dose-Response Relationship, Drug; Down-Regulation; Drug Resistance, Neoplasm/drug effects; Gene Expression; Humans; Leupeptins/pharmacology; Mitoxantrone/pharmacology; Multidrug Resistance-Associated Proteins/genetics; Multidrug Resistance-Associated Proteins/metabolism; Neoplasm Proteins/genetics; Plant Extracts/pharmacology; Protease Inhibitors/pharmacology; Protease Inhibitors/therapeutic use; Proto-Oncogene Proteins c-bcl-2/metabolism; RNA, Messenger/metabolism; Tamoxifen; bcl-2-Associated X Protein/metabolism