PROGRESS IN CANCER RESEARCH

New Zealand Listener, Volume 7, Issue 182, 18 December 1942, Page 14

PROGRESS IN CANCER RESEARCH

(Written for "The*Listener’ by DR.

H. B.

TURBOTT

Director of the Division

of School Hygiene, Health Department)

N our, country, cancer deaths are slowly increasing; in the five years 1936 to 1940 inclusive, the rise was from 1762 to 1858, or, in rates per 10,000, from 11.81 to 12.02. One of the reasons for the rise is that both curative and preventive medicine save more people, so that increasing numbers reach those later ages prone to cancer. That the risk of cancer increases with age is readily apparent. In 1940, 92 per cent of deaths occurred at age 45 years and upwards, and 51 per cent at 65 years and over. Now, for every death from cancer, it is calculated that there are about three living cancer patients, On this basis, there are in our land 5,574 persons with cancer. Is there any progress in cancer research? Cancer research only dates back about 40 years. It is now gaining momentum, and plenty of facts are coming to light. It is established that cancer . is not caused by germs or organisms, and therefore is certainly not infectious. It is quite safe to havo a cancerous patient in the house, In the laboratory

under artificial conditions it has been possible to implant cancer cells from one mouse to another of the same breeding. But such cells won’t grow in different breeds of mice or in other animals, Nobody has succeeded in producing cancer in animals by transplanting human cancer cells. When different breeds of mice are inbred, it can be shown that the susceptibility to cancer varies for the various types of cancercancer of the breast, lung or liver will be high or low according to the particular strain of mouse, It has been proved then, that cancer is a body cell disease. It can’t be passed from one animal species to another, and that it is highly specific for each cell type. What Produces Cancer? : In 1915, it was proven in rabbits and mice that long-continued application of coal tar caused skin cancer, and this led to the protection of workers and the prevention of cancer in industries handling coal tar, X-rays, radium, and ultraviolet light will produce cancer unless the body is adequately protected from continuous exposure to the rays. Many chemicals have cancer-producing properties; approaching 300 are known. Chronic irritation of the tissues is not essential to produce cancer. Tiny quantities of some of these chemicals can start a cancer in animals-the cancer grows of itself once started; the chemical is needed to initiate the change from healthy to cancerous cell. Are cancers caused by chemicals produced within the body? It has been demonstrated that large doses of female sex hormones can initiate breast cancer in animals. And research is proceeding to try and reveal other cancer-producing substances in the body. Just how a chemical substance or radium, X-rays, or ultra-violet light can turn a healthy into a cancerous cell, is being studied; prevention hinges on the elucidation of this key fact. Cancer kills by growing and growing, abnormal or cancerous cells replacing healthy ones. In animals, research has made possible the retarding of this growth by giving diets deficient in vitamins and proteins. Central Mystery Still Unsolved Cancer used to be considered entirely a local disease. Recent research has shown differences in enzymes in cancerous cells and in the healthy cells from \fhich they arose. Also that a liver cancer transplanted under the skin of a healthy animal reduces the activity of a certain enzyme in the normal liver of that animal. A local cancer has distant effects. These and other facts are emerging from the world-wide research on cancer. A body of cancer knowledge grows while the central mystery remains-what condition is it that tips the normal into a cancer cell? While awaiting the key, all that we can do as we get older is to seek the early help of surgery, X-rays and radium at the first signs.of abnormalities that may be cancerous,