The human tumor in condi­tioned guinea pigs

The human tumor H. Ep. #3 maintained in rats could be transferred for 1-8 generations in treated guinea pigs. H. Ep. #3 grew in the subcutaneous and intramuscular sites in each host at the same time. The treatment with the combination of X-ray 250 r. and 80 mg/kg of cortisone turned out to be the optimal conditioning studied. The number of tumor takes averaged 95.7-100 per cent in the subcutaneous site in guinea pigs treated with optimal conditioning, but in the intramuscular site, the number of tumor takes was 65.2-93.8 per cent. Host mortality varied from 4.2-37.5 per cent in the hosts treated with optimal conditioning. The subcutaneous tumor weights in hosts treated with optimal conditioning averaged 3.3 gm, and their intramuscular tumor weights averaged 5.6-6.2 gm. Tumor weights in hosts treated with only cortisone averaged 1-2 gm in both subcutaneous and intramuscular sites. Histological findings. for the original tumors were found to be the same as that for the successful transplanted tumors in the guinea pigs. The malignancy of the tumor was evaluated by the criteria of anaplasia, invasion, rapidity of growth, and ease of maintenance of transplants. There was no metastasis found in any organs.