Johannes Clemmesen

Twin studies and other genetical investigations in the Danish Cancer Registry.

League, and working in close collaboration with the National Health Service, is an organization with the primary intention to register all cancer cases, for resbarch purposes. This is done through a voluntary system ; all hospitals noti.y their cancer cases to the registry, and these notifications are supplemented with death certificates for all persons who are known to have suffered from malignant diseases, including leukaemias, myelomata and brain tumours. From Clemmesens studies on occupational mortality from cancer in Denmark it was clear, already before the start of the Registry, that a complete investigation of the occurrence of cancer demAnded at least an estimation of the role played by heredity in the origin of various cancers. It-was thought to be especially valuable to carry out such an investigation alongside the mapping out of cancer incidence with regard to age, occupation, and other variables, and to compare the hereditary tendency shown by cancers of various sites in the same population and at the same time.

Mortality Rates for Cancer of Urinary Bladder in Various Countries

URETHANE has been shown to induce the initiating phase of skin carcinogenesis in mice, not only when applied locally (Graffi, Vlamynch, Hoffmann, and Schulz, 1953; Salaman and Roe, 1953; Roe and Salaman, 1954; Berenblum and Haran, 1955b), but also when administered by mouth (Haran and Berenblum, 1956). The fact that urethane (ethyl carbamate) has a relatively simple chemical structure, is water-soluble, is itself non-carcinogenic for skin epithelium in the mouse, and does not even elicit epithelial hyperplasia, or any other demonstrable evidence of skin irritation-so constant a feature of other initiating agents or skin carcinogens, renders it all the more attractive a tool for the study of the nature of initiating action. Before one could effectively exploit urethane for this purpose, some quantitative data were needed about the conditions under which its systemic initiating action operated. The results of such a quantitative study, presented here, are concerned with (a) variations in total dose of urethane, given once only by mouth; (b) different numbers of urethane feedings, totalling the same overall dose; (c) different routes of administration of urethane, e.g. by mouth, intraperitoneally, subcutaneously, and topically applied to the skin; and (d) variations in the interval between the end of initiating action (urethane by mouth) and the commencement of promoting action (croton oil applied repeatedly to a small area of skin).