The survival and metastatic spread of homografts of mouse tumors in mice pretreated with lyophilized tissue and cortisone.

conditions the prior injection of lyophilized (11, 14, 15) or fresh tissues,' or antiserums to these tissues (10), into mice of a given inbred strain will lead to a breakdown of the normal resistance of these animals to tumor homografts. It has been further reported by Molomut and co-workers (li, 16) that the combined injection of frozen-dried tumor tissue and cortisone into mice led to the rapid appearance of â€oeextensiveintra abdominal sarcomatosis,†• which they considered to be metastases from subcutaneous tumor homo grafts. Occasionally, intrathoracic metastases were also present (16). The sarcomatosis was found as early as 14 days after tumor grafting (12). The authors (12) state that â€oe.. . we were able to pre diet our results based on our tentative hypothesis of mechanism. .. ,â€oe the hypothesis being that: (a) the injections of frozen-dried tumor and the subsequent live tumor graft constituted a â€oesys temic trauma,†• permitting the successful growth of the tumor homograft; and (b) the injection of cortisone would be an additional debilitating ex perience which should serve to further enhance the growth of the homograft to the point where exten sive metastatic spread would occur. It is these postulates of mechanism, particularly that of a general systemic trauma, that led us initially to conduct the experiments to be reported below. Our questions stemmed chiefly from pre vious observations that there is a definite speci ficity, both at the species level (3, 8) and within the species (4, 14),' which predicates whether or S Supported in part by grants-in-aid from the American not prior injections of tissue will lead to a break down of resistance to tumor homografts. Thus, lyophilized tissues from the rabbit, hamster, gum ea pig, and rat are ineffective when tested against tumor homografts in the mouse (8), and, in gen eral, tissues from one inbred strain of mice, when tested against a transplantable tumor indigenous to an unrelated inbred strain, are also ineffective (4, 14).' Could these observed specificities be abrogated by the administration of cortisone? We also wished to ascertain whether the re ported potentiating effect of cortisone would hold true for a host-tumor graft combination different from that previously used (12, 16). The first experiments we set up were directed solely to these questions. However, it soon became clear that not only could we not negate the spec ificities, but we were unable to duplicate the ob servations …