The relationship between hormone-induced tissue growth and neoplasia: a review.

This review will present a general appraisal of existing information rather than a detailed or corn prehensive review of the subject to be discussed. The terms to be employed require some defini tion. “Hormone-induced tissue growth― refers to an increment in tissue mass resulting either di rectly or indirectly from the action of exogenous or endogenous hormones or hormone-like substances. Such increments in tissue mass may involve one or several end organs, or, as in the case of the growth hormone, all the tissues of the body may be af fected. The increased tissue mass may represent actual cellular proliferation or increased cell size. Moreover, the increased mass may in some in stances be contributed to by secretions, interstitial fluid, ground substance, or even increased vascu larity of the hormone-sensitive organ. Thus, the term “growth― in this discussion is employed in a broad sense. “Neoplasia―is the formation of a tissue not regularly encountered in organisms of a given generic group. Accordingly, the term neoplasia may be properly employed only when the observer has an adequate knowledge of the regularly en countered variations seen in the tissues of the par ticular form under study. In keeping with these definitions it is clear that hormone-induced tissue growth will have in some instances certain features which set it apart from neoplasia, and in other instances the differences may not be very decisive. In this discussion it will be our aim to review the interrelationship between these two forms of new tissue formation in the light of the more significant observations in this field.