Genistein: An isoflavonoid derived from soy products. It inhibits PROTEIN-TYROSINE KINASE and topoisomerase-II (DNA TOPOISOMERASES, TYPE II); activity and is used as an antineoplastic and antitumor agent. Experimentally, it has been shown to induce G2 PHASE arrest in human and murine cell lines and inhibits PROTEIN-TYROSINE KINASE.Isoflavones: 3-Phenylchromones. Isomeric form of FLAVONOIDS in which the benzene group is attached to the 3 position of the benzopyran ring instead of the 2 position.Phytoestrogens: PLANT EXTRACTS and compounds, primarily ISOFLAVONES, that mimic or modulate endogenous estrogens, usually by binding to ESTROGEN RECEPTORS.Estrogens, Non-Steroidal: Non-steroidal compounds with estrogenic activity.Anticarcinogenic Agents: Agents that reduce the frequency or rate of spontaneous or induced tumors independently of the mechanism involved.Soybeans: An annual legume. The SEEDS of this plant are edible and used to produce a variety of SOY FOODS.Equol: A non-steroidal ESTROGEN generated when soybean products are metabolized by certain bacteria in the intestines.Protein-Tyrosine Kinases: Protein kinases that catalyze the PHOSPHORYLATION of TYROSINE residues in proteins with ATP or other nucleotides as phosphate donors.Plant Preparations: Material prepared from plants.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Soybean Proteins: Proteins which are present in or isolated from SOYBEANS.Soy Foods: Foods made from SOYBEANS. Health benefits are ascribed to the high levels of DIETARY PROTEINS and ISOFLAVONES.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Ovariectomy: The surgical removal of one or both ovaries.Tyrphostins: A family of synthetic protein tyrosine kinase inhibitors. They selectively inhibit receptor autophosphorylation and are used to study receptor function.Vanadates: Oxyvanadium ions in various states of oxidation. They act primarily as ion transport inhibitors due to their inhibition of Na(+)-, K(+)-, and Ca(+)-ATPase transport systems. They also have insulin-like action, positive inotropic action on cardiac ventricular muscle, and other metabolic effects.Lactams, Macrocyclic: LACTAMS forming compounds with a ring size of approximately 1-3 dozen atoms.Quinones: Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.Estrogen Receptor beta: One of the ESTROGEN RECEPTORS that has greater affinity for ISOFLAVONES than ESTROGEN RECEPTOR ALPHA does. There is great sequence homology with ER alpha in the DNA-binding domain but not in the ligand binding and hinge domains.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Benzoquinones: Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.Flavonoids: A group of phenyl benzopyrans named for having structures like FLAVONES.Phenols: Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.