Further Studies of Polymers as Carcinogenic Agents

The inception of this investigation is an exam ple of serendipity, a word recently popularized to designate the faculty of accidentally making ob servations or discoveries which were not originally sought. In the present instance, a safe antihyper tensive compound was being sought among the quinones to reduce the high blood pressure pro duced by wrapping one or both kidneys of rats with cellophane. After a couple of years, in seven of these rats malignant sarcomas had developed at the site of the wrapping. In several instances, these sarcomas had extended into the peritoneal cavity and had also metastasized. In view of this unexpected finding, a new series of experiments was begun to investigate this phenomenon in van ous directions. It was found that sarcomas could be induced not only by wrapping the kidney in cellophane, but alternatively by imbedding the cellophane subcutaneously in the anterior abdom inal wall. By either of these methods, tumors were induced in approximately 35 per cent of the ani mals (10). Further work soon showed (11, 12) that we were dealing not merely with one more carcinogen, of which hundreds were already known, but that we had chanced upon an entirely new group of carcinogenic substances, the polymer films. In 1941 Turner (13) had observed, also accidentally, that disks of Bakelite implanted subcutaneously in rats produced fibnosarcomas. Subsequent to our original report in 1948, similar results have been obtained by Druckrey and Schmllhl (4, 5), Zol linger (15), Laskin, Robinson, andkWeinniann (7), and Bering'. While, thus, there can be no doubt