Phenotype of the Swarm Rat chondrosarcoma varies based on tumor transplantation site. (A)Tumor weight following transplantation into different sites. The average tumor weight and standard deviation are shown. The weight of the subcutaneous SRC tumor was calculated from 6 animals. The tibia SRC tumor weight was calculated based on tibia tumors isolated from 14 separate animals. The lung tumor weight represents the average weight of individual tumor nodules collected from 7 animals. The lung tumors were isolated from animals that had SRC tumor transplanted into the tibia (7 of 14 animals had lung tumors). (B)Transplantation of the SRC tumor into the tibia of Sprague-Dawley rats. Histologic micrograph at day 34 revealed increased tumor volume and invasion of the tumor into the bony cortex. Cells stained with safranin O and fast green. (C)SRC tumors detected in the lung of a rat that had the SRC tumor transplanted into the tibia. Note the presence of multiple SRC tumors. Lung tumors were detected in 50% of the animals that had the SRC tumor transplanted into the tibia. The number of lung SRC tumors in a single animal ranged from 1 to 54 (average = 10). The average size of the tumors was 2 mm. No lung tumors were detected in the animals with subcutaneous tumor transplants.