Studies on Tumors’ Variability

Abstract

Progressive HC action on H₁₀Z zig-zag in vivo/in vitro transplanted Syrian hamster tumor is studied, and the following biological, cytological and cytogenetical modifications were obtained. (1) Giant cells and atypical mitoses, representing morphological characteristics of early experimenting stages. (2) Decrease in tumor growth and the appearance of a great chromosome number values dispersion, starting with the concentration of 275 μg/ml HC. (3) Tumor HC resistance, biologically characterized by a return to a high rate of growth and genetically by the presence of a heteroploid cell type with a new markerchromosome, by elevating HC concentration beyond 500 μ/ml. The occurrence of this tumor cell type in control tumor too, as well as its selection in later stages of the experiment only, suggest the role of induction-selection mechanism in these tumor modifications.