Summary
Yoshida Ascites Hepatoma 7974 has been studied during its early phases of growth within the embryonic liver following intravenous inoculation into the chick embryo. Multiple ultrastructural changes were seen within tumor cells in the liver in the first 24 hours, prior to any evidence of cell division. Observed changes included aggregation of ribosomal particles and enlargement of annulate lamellae, seen in both rapidly growing tumor from the rat and in the chick embryo system, and enlargement of mitochondria, accumulation of lipid vacuoles, and synthesis of glycogen, which were unique in the chick embryo host. These changes probably reflect a more active metabolic state induced in the tumor cells by the new environment. The possible relationships of these changes to the invasive process and to the chick host are discussed.
This investigation was supported by Research Grants P-442 and In 58G from the American Cancer Society. The work was also aided by Research Grant 950 from the Damon Runyon Memorial Fund and by NCI Grants GM10269 and CA10686 (research grants), and GM135 (training grant) from the National Institute of General Medical Science. Also supported in part by American Cancer Society Grant PRS-23 to P. J. G.