Changes in mouse skin cyclic nucleotides during chemical carcinogenesis and tumor response to treatment with BCG, L-Dopa and cyclic DBAMP.

During chemical carcinogenesis by 9, 10-dimethyl 1,2-benzanthracene the cyclic AMP and GMP content was measured in the skin of mice. The tissue of the developing skin tumor is characterized by an elevated cyclic GMP- and a lowered cyclic AMP level. Consequently the quotient of cyclic AMP and GMP is greatly lowered and is discussed as a crucial factor of cell derangement. Complete regression of the tumor is to be achieved by increasing the cyclic AMP levels by means of cyclic DBAMP and L-Dopa in 20% of the experimental animals. Additional stimulation by BCG of the unspecific immune defence has a favourable effect on tumor regression (about 50%). In a different type of tumor (solid Ehrlich carcinoma) it was possible after pretreatment of the mice with L-Dopa, cyclic DBAMP and BCG and after treatment following tumor injection to prevent tumor development in 67% of the animals.