Ni3S2-induced leiomyosarcomas in rabbit skeletal muscle: analysis of the tumoral myosin and its significance in the retrodifferentiation concept.

Leimyosarcomas were induced in rabbit skeletal muscle by Ni3S2 implantation. Tumor myosin was isolated and compared with normal adult muscle myosin and cow uterine smooth muscle myosin. This study has shown that this leiomyosarcoma myosin precipitates as long fusiform filaments and possesses two light-chain of 25000 and 18000 daltons as does the once-fetal type. The biochemical findings demonstrate that tumoral stem myoblasts originate from retrodifferentiated muscle cells.