The natural and induced resistance of mice to the growth of cancer

Abstract

In the present paper we purpose to give an account of experiments conducted during the past three years on the means whereby mice may be completely protected against the inocluation of transplantable carcinomata, which grow readily in normal mice. At the same time we shall show that these experiments throw fresh light on the nature of cancer. The Executive Committee and the Pathological Sub-Committee of the Imperial Cancer Research Fund have been informed of the progress of these investigations, and some provisional results have also been laid before the General Committee at the Annual Meetings. The experiments are being continued, but some of the results which have accumulated make it advisable to give an account of the stage at which they have now arrived. They are based mainly on a study of 23 transplantable carcinomata of the mamma of the mouse, and of other malignant new growths which could not be propagated artificially. In these experiments we have used, for the most part, the growth of Jensen’s tumour in normal animals to bring out the changes induced in protected animals and the refractoriness of insusceptible animals; but we shall also employ another tumour (XXVII) of different histology, which grows equally well under artificial propagation. We have employed Jensen’s tumour as a standard for the following reasons:-(1) It was the only tumour used to control some of our earlier observations; (2) With proper precautions it gives regularly 85 to 100 per cent. of successful inoculations in a large number of animals; (3) Within ten days the inoculation of 0.01 to 0.02 gramme in weight; (4) We have fully demonstrated that it may produce large metastases, that it may extend by the blood or lymphatic streams, and behave under experimental conditions typically as a malignant new growth; (5) Its rate of growth is not exceeded by any mouse tumour now being propagated; (6) It is in the hands of most investigators throughout the world, who will be able to repeat our observations. It therefore fulfils better than any other tumour the requirements of such a standard.