Metastasis from squamous cell carcinomas of SENCAR mouse skin produced by complete carcinogenesis.

The incidence of metastasis was evaluated in female SENCAR mice after induction of squamous cell carcinomas by repetitive applications of either benzo [a] pyrene (B [a] P) or N-methyl-N'-nitro-N-nitrosogaunidine (MNNG). Between 41 and 50 weeks 50% of the animals with carcinomas in the B [a] P group had metastases, whereas 20% had metastases in the MNNG group. Very few metastases were observed before 40 weeks of treatment. The major site of metastasis was the lungs; however, metastatic tumors were also found in lymph nodes, adrenal glands and kidneys.