Malignancy of neurogenic cells characterized by their invasiveness in vitro

15 continuous neurogenic cell lines, originated from the off-spring of ethylnitrosourea treated BD IX rats are screened for invasions in vitro. Confrontations of precultured embryonic chick heart fragments with aggregates of the neurogenic cells are studied in a three dimensional system. Invasion of the neurogenic cells into the heart fragment is scored on histological sections. Invasion in vitro was correlated with malignancy in vivo. The reproducibility in our experiments strengthen the idea that invasiveness in vitro is a criterion of malignancy. Different cell lines express various patterns of invasion in vitro. Alterations are observed as well in the invading cells as in the heart tissue. These alterations represents cellular activities during invasion. The observed activities are probably the result of cell growth, penetration, destruction and phagocytosis.