Participation of teratocarcinoma cells in mouse embryo development.

Teratocarcinoma cells (OTT 6050) from 129 SvSl C P mice were transferred into blastocysts from random bred Swiss albino mice. The blastocysts were placed in the uteri of foster mothers and the adults resulting from these blastocysts were studied for evidence of an effect of the transferred malignant cells. Sixty adults resulted from the experiments, and one of the adult mice that had received teratocarcinoma cells in the blastocyst stage showed several stripes of agouti hair. All the adult animals received grafts of skin from animals identical to those supplying the cells. The animals that resulted from blastocysts into which cells had been transferred maintained skin grafts for a significantly longer period than did controls. These experiments indicate that the transferred malignant cells were able to establish small colonies in the embryos and that some of these cells persisted into the adult.