Sectional analysis of tumor colony growth in the soft-agar assay: effects of oxygen.

Soft-agar clonogenicity of L1210 mouse leukemia cells and of xenografts of a human melanoma and a carcinoma of the cervix was studied sectionally by the sizes of the colonies grown under hypoxic gradients and aerobic condition. Soft-agar plating efficiency was increased in cultured L1210 cells with decreasing oxygen concentrations. The growth of both cultured L1210 cells and their BDF1 ascites was better in 5% oxygen than in 20% oxygen. Although soft-agar colony development of both melanoma and cervical carcinoma was significantly better in 5% oxygen, the former has a secondary preference for a hypoxic atmosphere and the latter, for an aerobic condition.