Growth of a chemically induced transplantable fibrosarcoma (SCFSI) was observed 2 wk after i.v. injection of tumor cells into histocompatible B2/B2 (SC) chickens. Approximately 30% of recipients had tumor nodules in the stomach mucosa and pancreas, 10% in the lungs and less than 10% in the heart. No relationship between initial localization of 51Cr-labeled SCFSI cells and sites of tumor growth was seen. Labeled cells localized primarily in liver (50%), lungs (24%) and spleen (3%). Total-body irradiation with .gamma. rays greatly enhanced tumor growth in stomach, pancreas, kidneys, heart, lungs, skeletal muscles and liver, but tumor nodules were not detected in spleen, thymus gland, bursa or brain. Repeated i.v. injections of Corynebacterium parvum [Propionibacterium aches] prevented tumor growth in irradiated and normal chickens. Recipients 1 wk old showed as much tumor growth with or without irradiation, which suggested that the effect of irradiation in older recipients was partly due to damage of the immune response. Agammaglobulinemic chickens did not show more tumor growth than did normal recipients. Prior injection of soybean trypsin inhibitor did not prevent the enhanced tumor growth caused by irradiation, although this inhibitor is known to protect against the damaging effect of irradiation on blood vessels in the chicken. Tumor cells from 2 additional SCFS lines (II and IV) also grew in the stomach and pancreas, but SCFSII was never found in heart or skeletal muscle, even in irradiated chickens. The sites of tumor growth were determined by various factors including local effects such as favorable environmental for growth in certain organs, immunologic resistance and possible blood flow or vascular influences.
