Sex Hormones and Their Relation to Tumors

Abstract

In an earlier period it was shown that an ovarian hormone interacting with hereditary factors is responsible for the development of mammary gland carcinoma in mice. It was shown, furthermore, that the number and age of the mice so affected depend in a quantitative manner on the length of time during which the hormone has a chance to act on the recipient tissue, or, expressed differently, on the total quantity of hormone given off during this period. By diminishing this time and the quantity of hormone, the incidence of tumors can be diminished proportionately, and if a certain threshold has been reached the appearance of tumors can be prevented altogether. Strains and families of mice can be separated, which, in accordance with their hereditary characteristics, respond with very unequal readiness to approximately the same quantity of hormone. An analysis of the sexual cycle made it appear probable that, of the two ovarian hormones, it is the follicular hormone which is responsible for this effect. These investigations have also shown that a relatively small quantity of the hormone, sufficient to induce estrus if acting at regular intervals, is enough to accomplish the carcinomatous transformation of normal mammary gland tissue in that number of individuals which accords with the degree of the hereditary tendency of the family or strain to which they belong. From these investigations it seemed probable that in males mammary gland cancer appears only exceptionally because here the amount of available estrin remains below the threshold. During this period, therefore, the first attempts were made to produce mammary gland carcinoma in male mice (1) by means of transplantation of ovaries into castrated males, and towards the end of this period Murray (2), who also used this method, succeeded in a number of cases.