Estrogens plays an essential role in the etiology of human breast, ovarian and endometrial carcinoma. Activation of estrogen receptors contributes to the growth and metastasis of these common estrogen-dependent tumors found in women. Recent studies reveal that melatonin, main hormone secreted by pineal gland, has been involved in the regulation of cancer cells growth. The oncostatic properties of this molecule has been considered on different kinds of tumors but especially on hormone dependent breast cancer.

Breast cancer is one of the most often female cancers. From the last few years in Poland morbidity increased about 4 5%. This cancer is also cause of the major part of deaths caused by malignant tumors. Etiology of most cases of breast cancer is not possible to determine. The most important risk factors are age and breast cancer occurrence in first and/or second step relatives. Germinal mutations in two major high penetrance genes, BRCA1 and BRCA2 are responsible for high risk of cancer development but they constitute less than 5% of all cases of this cancer.

Phytoestrogens are biological active substances present in many plants. Phytoestrogens, mycoestrogens and xenoestrogens belong to so called environmental estrogens which may affect different biochemical processes in animals. In the review we attempt to present current knowledge on classification and occurrence of phytoestrogens as well as their metabolism and biological effects in females.

Matrix metalloproteinases (MMPs) are the enzymes which are directly involved in metastasis. Under physiological conditions MMPs are involved in such processes as embryogenesis, angiogenesis, cyclic changes in endometrium, wound healing and platelet aggregation. There is evidence that MMPs activity changes in many pathological conditions, including tumor disease, inflammatory and the degenera- tive diseases of nervous system. In cancer MMPs regulate growth and cancer-cell proliferation, metastasis, angiogenesis and the immune response to cancer.