Observations on H ₁₀ ZE Mixed Tumor

In this study one describes the experiment of zig-zag in vivo/in vitro transplantation of 2 heterologous tumors, (H<sub>10</sub>Z solid hamster tumor and Ehrlich ascitical mouse tumor) arising a mixed tumor which is transplantable in hamster and in mouse presenting the following characters: (1) Biological evolution as a peritoneal dissemination of solid tumors and ascitic fluid rich in neoplastic cells. (2) Morphological disposal of tumor cells in epithelial islands surrounded by a connective tissue, in solid peritoneal tumors. (3) Heterogenous genetical structure with the presence of metaphases of H<sub>10</sub>Z tumor, Ehrlich ascites and certain hamster and mouse metaphases of special features. The role of hybridization phenomenon in the appearance of these tumor characters is discussed.