Teratocarcinoma cells cultured on embryonic substrates show accelerated migrating behavior in vitro and increased metastatic activity in vivo.

Teratocarcinoma cells (402AX) were grown on feeder layers of whole mouse embryos (Day 4) or mouse embryonic fibroblasts and then were either examined in vitro or transplanted in vivo. After twenty-four hours of coculture, teratocarcinoma cells demonstrate accelerated cell migration in vitro. Furthermore, transplantation of teratocarcinoma cells with embryonic substrates into syngeneic hosts produces grossly detectable lymph node metastases. These effects appear to be due to soluble factor(s) produced by embryonic substrates which enhance tumor cell proliferative/migratory activity. This suggests that tumor cell invasion and metastasis may be stimulated by soluble factors produced by host tissues.