Abstract
The effect of methotrexate on solid rodent tumours has been investigated using the spontaneous mammary adenocarcinoma of the female C3H/Bts mouse. As these tumours exhibit a wide range of volume doubling times, calculations of tumour response to methotrexate must be related to doubling time. When methotrexate is injected into the tumour a dose-dependent tumour response is obtained. Systemic citrovorum "rescue" prevents methotrexate lethalities but reduces tumour response by a factor of 2. Methotrexate-treated tumours have an increased volume doubling time post treatment.