An inverse correlation (dose-response between 5-methyl-cytidine and the fate of spontaneous tumours in mice

Abstract

Tumour-bearing mice, 248 in number, have been injected with 5-methyl-cytidine dissolved in physiological salt solution. The mice were divided into 5 series depending upon the amount of 5-methyl-cytidine they received. Mice of a successive series received 43.2, 28.8, 14.4 and 7.2 mg/kg body weight. There was a progressive increase in the percentage of mice showing regression of tumours in the successive series, as follows: 45%, 50%, 65%, 60%, and 67.8% respectively, giving an average percentage of regressions of 59.7%. The incidence of mice developing multiple primary tumours increased in the same successive series respectively as follows: 25%, 43.8%, 58.3%, 73.3%, and 70%, thus giving an average of 58.3%. The evidence obtained indicates an inverse correlation (dose-response) between the amount of the 5-methyl-cytidine injected and the percentage of regressions of spontaneous tumours.