The effect of methotrexate on spontaneous mammary adenocarcinomata in female C3H mice.

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.