CANCER RESEARCH

Rotorua Morning Post, Volume 1, Issue 109, 30 December 1931, Page 7

CANCER RESEARCH

VIRUS THEORY BRITISH RESEARCH WORKERS MAKE IMPORTANT DISCOVERY NEW KNOWLEDGE DESCRIBED The problem of eaneer is being approached from so many different angles, by so many different workers, that there is always a danger of its details being magnified at the expense of the whole. That is why a book published by Drs. W. E." Gye and W. J, Purdy, members of the scientific staff of the National Institute for Medical Research, is one of the most interesting that has ever been written, and may very possibly prove to be one of the most important, says the medical correspondent of the "Daily Telegraph." For some years Dr. Gye has been recognised as one.of the most brilliant investigators at work in this country. In the present volume he is ehiefly concerned to establish a eontroversial point. But he has nevertheless been able, with his collaborator, to stand away, as it were, from his immediate preoccupation, and the result is as masterly and dispass/onate a view of cancer as has been penned in recent literature. Cancer, as Drs. Gye and Purdy remind us, has been known and described ever since the dawn of medicine. Lawless Growth Primitive races are afflicted with cancer, and so are lower animals, both domestic and wild. No habit of life, no dietetic peculiarity bas been shown to affect susceptibility. Though it may arise in almost any tissue of the body the eells which compose it always remain true to type and to the particular type of cell in which it happens to originate. But these cells have a lawless and apparently indefinite power of growth, and should they become detached from the main tumouiyhave the power of forming the nuclei of fresh secondary growths in other parts of the body. Turning to research, there have been, as Drs. Gye and Purdy remind us, three eardinal discoveries. German and Danish investigators were the first to show that cancer was of common occurrence in most vertebrate animals, and could be popagated artifically by means of cell grafts. Fibiger, of Copenhagen, Jamagiwa and Itchikawa, of Japan, showed that it could be produced de novo by prolonged extrinsic irritation. And finally Peyton Rous, of the Rockefeller Institute, New York, showed that malignant tumours in fowls could be propagated by cell-free filtrates of these tumours to other fowls. Cellular It is upon this last discovery that Drs. Gye and Purdy have based the greater part of the experimental work which is recorded in their volume. Before Rous' work it was generally. assumed that cancer, in its basic sense, was a strictly cellular j disorder, due to some inherent chemical or biological change in the constitution of the cell or its nucleus. J It was this that started it upon its lawless and independent - course of multiplication ; and it was only by . some individual member of the out- j law group that cancer could bp induced in a healthy animal or cause a secondary growth in its original host.

But Rous' work apparently upset this. In fowls, at any rate, he was able to induee growths with so small an injection as .OOle.c. of a filtrate from which every cellular element had been eliminated. Although no microscopical verification was forthcoming this filtrate behaved in a manner very strictly analagous to one containing - a living organism. And it was because of this that the theory of a virus, or sub-microso-pieal living agent of cancer, was first promulgated. For various reasons this theory has not yet obtained a full measure of scientific support. It has not yet been found possible, for instance, to induce growths by cell-free filtrates of mammalian cancer, their specificity to the particular kind of animal in which they occur, has seemed to involve the unlikely supposition of many kinds of cancer virus. The true malignancy of the Rous tumours has also been doubted. In face of the evidence now adduced, however, by Drs. Gye and Purdy, this latter point can scarcely be maintained. And it would seem diffieult, in view of accumulating observations and their own very careful experiments, to resist the conclusion that in fowls, at any rate, cancer is indeed the result of a living organism. But if in fowls why not in mammals, including human beings? That is the question put by Dr. . Gye, and though the arguments against it are undoubtedly weighty, they are mostly based, as Dr. Gye points out, on negative evidence. Probably the most eogent is the difficulty, already referred to, of assuming a common virus able to produce malignant growths of such diversity and so strictly specific to their particular breed of animal hosts; and the almost equally diffieult alternative of imagining a large number of different cancer viruses. Added "Something" This is a diffieulty, however, that Drs. Gye and Purdy have most ingeniously attacked. By a series of wellplanned experiments they have demonstrated that the cell-free filtrate which produces the Rous fowl tumours consists of two parts, a living one of virus, that can be destroyed by antiseptics, and another, probably derived from the invaded cells themselves, that can be destroyed by heat. Lacking either, the filtrate is innocuous. But they have gone even further. To a filtrate deprived of its virus they added "something" diffused from a similar malignant growth in a rat, They then found that the filtrate again beeame actiye and produced in a healthy fowl the typical original fowl tumour. If this is confirmed by other observers it will assuredly be one of ; the landmarks in cancer research, for it means that this "something," pre-' sumably a virus, can replace that re-

sponsible for the fowl tumour, although it comes from another species. Based upon this, and the whole body of their work, Dr. Gye and his collaborator have definitely come, therefore, to the conclusion that all cancer is caused by a common living virus acting in conjunction with another component, which is responsible for the peculiar, intensely specific, cellular reaction characteristic of • malignant growths. Neither can act alone, and the probability is, in the writers' view, that the cancer virus is widespread, and of relatively low infectivity. How it invades the body or meets i the requisite cell pre-condition that i enables it to become active is not yet : known. But if the material brought I forward by Drs. Gye and Purdy j triumphs over the tests that will as- • suredly be applied to it an advance | will have been made in our knowledge of cancer that it would be diffieult to exaggerate.