Local Origin of Fibroblasts deduced from Sarcomas induced in Chimaeras by Implants of Pliable Disks

Abstract

“THE origin of fibroblasts in healing wounds has been debated for over 100 years” according to Ross, Everett and Tyler¹, whose recent experiment indicated local connective tissue to be the source. Barnes and Khrushchov² had already concluded that in murine radiation-chimaeras precursor cells arose in bone marrow. We deduced from this that implants of pliable disks of adequate size, which give rise to local malignant growths (sarcoma), should in similar radiation-chimaeras produce sarcomas derived from the donor (myeloid) elements of the chimaeras and have examined such sarcomas induced by cellulose or silicone rubber. In the chimaeras the donated marrow was distinguishable from the host tissue by the presence in mitotic cells of T6T6 chromosomes in one or other phase. The sarcomas were analysed cytologically; also, tumours arising in allogeneic chimaeras were tested genetically by their capacity for continued growth in mice of both pure strains. Both tests indicate that the tumours arose from the native host cells and not from the donated myeloid cells or their progeny.