Cell-Free Transmission of Chemically Induced Tumours in Mice

Abstract

Cell free extracts were obtained from methylcholanthrene induced skin fibrosarcomas in NMRI mice. These extracts identified according to the age of the skin tumor nodule were injected intraperitoneally in mice and after 6 similar consecutive passages cell free extracts were prepared from the liver and spleen of these animals. This was followed by the injection of the extract intraperitoneally into newborn mice. Cell free extracts obtained from 14-18 day old skin neoplasms resulted in the development of tumors in 30 percent of 45 surviving mice. The rate of tumor development was higher in female mice and seemed to be dependent on the age of the tumor extract prior to the passage. Although the primary tumors induced by methylcholanthrene were fibrosarcoma of the skin, the cell free extracts from these tumors were inductive of adenoid epithelial neoplasms ranging from the benign adenoma to the papillary adeno-carcinoma. The majority of these tumors developed in the salivary glands of the mouse. It was noted that NMRI mice have not been known to develop spontaneous tumors of the salivary gland.