Extrauterine growth of mouse egg-cylinders results in malignant teratoma.

TLDR: Histogenesis and full differentiation are probably stopped by trophoblastic overgrowth, and fully differentiated adult tissues in rat egg-cylinder grafts maintained for 30 days in the anterior chamber of the eye are found.

Abstract: WHEN Stevens transplanted mouse ova at the one and two cell stage into the testis of a 129/Sv mouse, teratomas consisting of several types of differentiated and undifferentiated tissues resulted1. Tumours developed only when transplantation was into the 129/Sv-SlJCP strain, known for developing frequent spontaneous testicular teratomas. In other strains of mice, Stevens1 obtained no growth of tubal ova after transplantation into the testis. Kirby2 obtained only trophoblast and extraembryonic derivates after grafting tubal eggs under the kidney capsule and in the testis, but when he grafted blastocysts the egg-cylinder developed. Similar results were reported3–6, but the experimental period was too short (up to 15 days) for histogenesis. Nicholas7 reported histogenesis after the transfer of tubal eggs under the kidney capsule, but his experiments have never been repeated successfully. Histogenesis and full differentiation are probably stopped by trophoblastic overgrowth5,6. Grobstein8 and Levak-Svajger and N. S.9 found fully differentiated adult tissues in rat egg-cylinder grafts maintained for 30 days in the anterior chamber of the eye. They found no evidence of atypical or malignant cells.