Growth of Transplantable Cancer in Rats previously injected with Placental Tissue

Abstract

AN antigen in malignant and embryonic tissues capable of retarding the growth of a transplantable human tumour (HS₁) in rats has recently been described by Buttle et al.¹. Seven days after injecting a variety of human tumours and normal adult and fœtal human tissues into weanling rats, they challenged the animals with HS₁ and cortisone. Significant inhibition of tumour growth was produced by prior injection of homogenates of HS₁, sarcomata and a variety of normal fœtal tissues, especially spleen, whereas normal adult plasma and muscle had little if any effect. Buttle et al. attributed these findings to a labile antigen, destroyed by freezing and thawing, present in high concentration in embryonic and malignant tissue, and related to a high rate of cellular division in those tissues.