[Studies for a mathematical model of the proliferation kinetics of mammary carcinomas by means of electronic data processing (author's transl)].

Continuing an earlier publication in which the growth of spontaneous mammary carcinomas in female mice of a C3H inbred strain was described, in the present paper the growth rate is expressed by a mathematical function, and is adapted by electronic data processing to the experimental values of 60 tumors classified into seven "growth types". For mathematical description the tumors were conveniently assumed to have a spherical shape, and the main reason for the reduction in volume increase with increasing tumor size was thought to be insufficient supply with oxygen and the essential nutrients S. Including the experimental data of all carcinomas investigated, the minimum concentration of S necessary for mitotic activity of the tumor cells was calculated to be 65% of the normal level. As the average for all the tumors investigated, a time of at least 33 hrs is required for the tumor volume to double.