⁹⁰ Sr-induced Osteosarcomas in Radiation Chimaeras

Abstract

SummaryTo determine whether sarcomata of bone are derived from osteo-progenitive cells committed to bone production or from uncommitted pluripotent cells in bone-marrow, radiation chimaeras were injected intraperitoneally with 20 µCi of strontium-90. Both syngeneic CBA/CBA-T6T6 and allogeneic CBA-T6T6/A chimaeras were used. The resulting tumours were analysed cytologically for T6 chromosomes to determine whether they were of host or donor origin. The aneuploid cells of all 13 tumours analysed were of host-type: this was confirmed by genetic analysis in six tumours arising in allogeneic chimaeras.Euploid mitotic cells of donor marrow provenance were commonly seen in preparations of tumours.Tumours were also analysed in 11 of 14 normal mice, both CBA and CBA-T6T6, injected with 20 µCi of strontium-90. No false positive or false negative results for T6T6 were recorded.The bone-tumours were of at least two types, typical osteoblastic sarcomata and osteolytic sarcomata either fibroblastic or haemangioendotheliomatous.