Heterotransplantation of ovine squamous cell carcinomata into nude mice.

Twenty-five tumours sampled from various sites on sheep were implanted subcutaneously into nude mice. Of these, 10 were successfully transplanted and serially passaged. An association was found between the tumour growth site on the sheep and its acceptance as a xenograft, with those derived from the skin of the nose being the most successful. Both growth pattern (expansive or invasive) and the histological appearance of the xenografts were similar to that observed in the sheep although faster growth rates were observed after the tumour was serially passaged in the nude mouse.