The effect of an allergic inflammatory response in the tumor bed on the fate of transplanted tumors in mice.

became one of the basic technics in experimental cancer research, a huge number of publications have appeared re porting attempts to identify the mechanisms re sponsible for the success or failure of tumor grafts. An extraordinary number and variety of factors have been observed to influence the extent and rate of growth of tumor transplants. The possibility that an inflammatory response in the tissues of the host into which the tumor is transplanted might affect its development is at most universally accepted. Unfortunately, investi gations of this problem have yielded seemingly conflicting results. For example, Zahl and Nowak (3) observed that an inflammatory response in the subcutaneous tissues at the site of implantation, produced by excessive trauma at the time of im plantation, caused acceleration of the growth of Sarcoma 180 in mice. On the other hand, when Chambers and Scott (1), also using Sarcoma 180, produced the inflammatory response by injecting the tumor graft with starch grains, they observed an inhibition of its growth. Similarly, contradic tory results were obtained when the inflammatory response was produced by infecting the tumor graft before implantation or by introducing in fectious organisms into the graft site at the time of implantation. These are discussed in the recent review by Snell (i). In all the experiments cited above, the inflam matory response at the site of implantation was produced by using a tumor graft which had been altered in some way or by introducing an addi tional exogenous factor at the time of implants tion. This report concerns the effects on tumor grafts of an inflammatory response which may be considered entirely endogenous (i.e., one which S Supported (in part) by a grant from the American Cancer arises entirety within the tissues of the host at the implantation site and is independent of the nature of the graft and of the act of implantation). This was accomplished by using mice which had been sensitized by repeated injections of a crystalline antigen so that either a local or a systemic injec tion of that antigen produced an inflammatory re sponse localized to the tumor graft site. MATERIALS AND METHODS Since neither the direction nor the magnitude of the effect of such an inflammatory action upon the development of the tumor graft was known, two parallel experiments were performed. In one, a well established tumor was grafted into an inbred mouse strain in which it …