Growth of Sinclair swine melanoma in the hamster cheek pouch.

Specimens from seven Sinclair swine melanomas were transplanted to the cheek pouches of Syrian Golden hamsters. The specimens were taken from young swine and were derived from raised tumors that either were present at birth or developed after birth from flat melanocytic lesions as well as from apparently normal skin. All seven specimens grew in the hamster cheek pouch. One lesion, derived from a 3-day-old piglet, exhibited the most aggressive growth in the hamster and was successfully transferred to other hamster cheek pouches. These results confirm the malignancy of Sinclair swine melanoma and indicate that tumors of neonatal swine contain more malignant cells than those of older animals.