Patterns of invasive growth in vitro. Human decidua graviditatis confronted with established human cell lines and primary human explants.

Human decidua graviditatis was used as a receptor tissue to demonstrate invasive properties of human cells in vitro. In the confrontation between decidua and established cell lines of tumors and of normal origin as well as primary explanted cells, we noted differences in the cells' interactions with decidual tissue. The two original tumor cell lines, HeLa (carcinoma) and AFi (sarcoma), and a spontaneously transformed lymphoblastoid cell line showed aggressiveness, i.e., invasion, rapid proliferation, injury, and destruction of the decidual tissue. Strain HeLa S3 and two established cell lines, FL (amnion) and Girardi Heart, which are regarded as transformed cells because of their increased mitotic rate and polyploidy, exhibited various degrees of aggressiveness but did not invade. Freshly explanted fetal lung and endometrium caused no injury to the receptor tissue and were included in the decidual tissue.