A possible role of estrogens in carcinogenesis of non-target tissues.
The mitogenic action of the estrogen-receptor complex is supposedly similar in both normal and malignant target tissues. As receptors are present in several types of non-target tissues, in the case of lesions at the nuclear acceptor sites, the complex in those might be able to cause successive mitoses. Estrogen-dependent tumors of non-target tissues have been reported by several investigators. In normal and malignant cells of the breast and some other types of non-endocrine cells, the ability to produce their own estrogens (from circulating precursors) has been shown. The locally formed estrogens might have a role in the initiation of some malignant transformations. Indications of this process are the switching to estrogen production of some neoplastic endocrine or undifferentiated cells, certain ectopic effects displayed by some cancerous tissues, and the possible roles of GH, PRL and cholesterol in the development of some malignancies. The present endocrine system for the synthesis of the sexual hormones might be a specialization of a system at the cellular level. Polypeptide hormones might evolve from regulatory parts of cyclases or phosphodiesterases. Traces of the original biological processes might still be maintained by several cell-types.
D000818:Animals; D005075:Biological Evolution; D002467:Cell Nucleus / Q000502:physiology; D004967:Estrogens / Q000502:physiology*; D006801:Humans; D008938:Mitosis; D009369:Neoplasms / Q000209:etiology*; D011956:Receptors, Cell Surface / Q000502:physiology*
D004967:Estrogens; D011956:Receptors, Cell Surface