MYSTERY OF CANCER

Rotorua Morning Post, Volume 1, Issue 132, 27 January 1932, Page 2

MYSTERY OF CANCER

a Medical Correspondent)

DR. 3Y|:'S THEORY A ' ' —————— PROSPECTS OF PREVENTING RAVAGES OF DREAD " -DISEASE/ , . „ / IMPORTANT DISCOYERIES

(By

The work done by Drs. Gye and Purdy on the cause of eancer has a dublic as well as a technical interest. Yet to give a simple account of it is far from easy. : Perhaps it will be best to begin by setting out the conception of cancer ■\idiich is universally held at the present time. • The animal body is built up of eells, microscopic protoplasmic masses which d'iffer according to the issue df which1 they fotm a'part. Ordinary bacterial disease can be regarded as diseases of the body as n whole; but cancer is peculiar in being a disease strictly limited to cells and cah hardly be looked upon as a disease *of*the whole body. If we take a skin cancer as an example we find that it is a'stsictly local diSease. It consists of a steadily growing mass of ce]ls. Growth of the mass .is due solely to the ' multiplic'ation of cancerous cells and is entirely independent' of the needs of the body. This growth solely by m'ultiplication of its own cells, the growth being uncorttrolled by the regulating force's df the body, is the outstanding cKaracteristic of cancer. Indeed, it is the, only. known characteristic of cancer. Explairf this quality and cancer is explained: Spread of the disease to distant parts of the body takes place only when cancer cells become detached from the parent mass and are carried by blood or lymph stream to new sites.

One Type of Cell Each cancer consists of one type of cell. Thus in our example all the cells of the skin cancer would be of the shme kind and would resemble normal Skin-cells in everything except that noi'mal cells do not show the cancerous urge tb multiplication. Cancers differ from one another in the kind of cells of which they are composed; thus our cancer of the skin would differ from a cancer of the brain or a cancer of the stomach. Thbre is an enormous number of different kinds of cancer, which is only what is to be expected if, as is universally believed, each and every cell of ,the body represents the potential . starting point of a cancer. This infinitude of kinds of cancer is a s'econd feature -of the disease calling for explanation. No evidence that mammbli&n cancer is an infective process has bden hitherto obtainable., and it seems unthinkable that each and every one of the different recog;nised kinds of cancer can be caused |by a different kind of micro-organ-ism. . * Cella are as numerous as the dififerent var'ieties of cancer; but it is jnot so with micro-organisms, arid this j consideration has seemed finally and ; decisively to exclude all possibility . that cancers can be caused by living organisms. The opinion has become ifirmly established that cancer is a morbid derangement of the cells. An Important Discovery The first indication that the present views are wrong came when Peyton Rous and his colleagues at the Rockefeller Institute, New York, discovered that in certain naturally occuring cancers of the common fowl a causative agent can be separated from the cancer cells. It was found that an extract of one of these cancers — say of the cancer now generhlly knoWn as the Rous Sarcoma No. 1 — may be made in a weak solution of common salt and then filtered free of all cells and cell debris, and that still the filtered cell-free extract will cause the formation of tumours when injected into normal fowls. Clearly, the transihission of these tumours from one host to another 4oes not depend upon the transplantation' of -livitig cells. That which passes over and starts the new tumour is something obtained from the cells. Here, then, is proof positive that current theories do not

apply to these cancers; and, not applying to these cancers, they cannot constitute a true explanation of th€ essential cancerous properties. The next problem is the discoverj of the nature of these casual agents. On the one hand, these agents are found to multiply pari passu with the growth of the tumours indefinitely — and multiplication is the outstanding characteristic of living things. The agents pass through filters which hold back even the smallest oi the common bacteria just as viruses do; But", on the other hand,' since these filtered .extracts produce only tumours of the same type as that frorff "which they have beert prepared, it follows that each different tumour must contain & different causative agent, and we are back again at the oldj and "apparently insuperable, ohiection to a living cause, namely, ho'w can micro-organisms be as numerous and as specific as the tumour agents are? New Path of. Inquiry Pi'S. Gye and Purdy appear to have estahlishe'd thiat the tumour agents af e ' compiex, and that their properties 'liav'e beeh puzzling simply because the complexity has not been suspected. ' 1 One part seems not to be fowl in nature; it has not the constitution which distinguishes the • constituents of the body. of a fowl from the constituehts of other ahimals — a duck, for instance. It is foreign to the fowl and has all the qualities of a living of ' mrdf o-org"ahism | it is, iii fact, a virus. Another p'art' of the .agent is derived *ff om . the cancer cells; themselves, is-fowl in nature, and has the highly specific characters which we associate oftly with delicate * cell proteins. The " important point to graSfi here is that infection by means of a" filtered' tumour extract is dependent tip'on the co-operation of these two elements of the compiex agent; neither can act alone. The- diffietflty concerning the multiplicity of "Viruses "is found; to he explhirted qtiite easily. The type of tfifiidil'f depefidS" almost solely: upott the f^pe'of :cell which is'entered by the virus at' the initiation of the tumour; so that whatever determines the kind of cell which is infected by the virus determines the kind of canfcer "wliicK' resultS. Thus the multi-|

plicity which is demanded is found-to be not a multiplicity of viruses ■ as had been supposed but of cell derivatives and we know that different kinds of cells have different chemical constitutions. * This, then, in broad outline, is how things stand at present. What is tfie practical value of this new work? Its first result fiiay he to displace the present views of cancer and drive more people to work along new lines. Secondly, once it is admitted as established that a virus causes cancer most of the terrors of the unknown will disappear. Thirdly. since Drs. Gye and Purdy claim that it is possible to cause anti-substanees to the virus to form in the blood of animals it follows that if they can sort out and label the viruses of mammalian tumours prevention of cancer will become practicable.