Rate of metastasis from C3H mouse mammary tumours.

Transplants from the same C3H mouse mammary tumour have been used for radiobiological experiments with curative intent for more than 8 years. During that time, the rate of metastasis to the lungs has varied between 0 and 63% and an explanation has been sought for this change. The results of immunological assays showed no obvious pattern. An inverse relationship was found between tumour latency and metastasis.