Morphology of the transplantable colon carcinoma derived from the spontaneous colon carcinoma of WF-Osaka rat strain.

Two lines of the transplantable colon carcinoma were established. They were from the spontaneous colon carcinoma of WF-Osaka rat strain which had been set up in our laboratory. Transplant procedure was carried out mainly by the intraperitoneal implantation, and, in particular, the treating with a specified way of HIBITANE for disinfection against colonic flora at the primary transplant was quite effective. The growth speed of the transplanted colon carcinoma was slow at first and gradually increased its speed. Histology of the transplanted tumor altered gradually from the glandular pattern at first to the medullary pattern in the late stage of the transplant generation. Each tumor node in the late stage of transplant generation was composed of numerous small nodules separated by thin stromal tissue. Squamous metaplasia and central necrosis were seen in the center of the small nodules. Two lines of the transplantable colon carcinoma were named C1 and C2 and the former is at now the 101th generation and the latter is at the 107th generation.