Normal and malignant trophoblasts do not recruit granulated metrial gland cells.

A possible relationship between the development of granulated metrial gland (GMG) cells and trophoblast was studied. Trophoblast implanted in ectopic sites (e.g. kidney capsule) did not induce decidua and did not recruit GMG cells. Only when injected in utero did trophoblast lead to the development of decidua and to the recruitment of GMG cells. With malignant trophoblast (choriocarcinoma cells) similar results were obtained as with normal trophoblast both after ectopic or after in utero injection. The presence of decidua, but not the development of a conceptus or the outgrowth of trophoblast, seems to be required for the differentiation of GMG cells.