Effects of MPA on the invasive capability of the parent Ishikawa cells and the progestin-resistant Ishikawa cells. Cells were treated with MPA (1 μM) or vehicle for 72 h prior to being harvested and loaded into Matrigel chambers. After incubation, invading cells were stained with HE and photographed at ×200 magnification. (A) Parent Ishikawa cells, vehicle control; (B) parent Ishikawa cells, MPA; (C) progestin-resistant Ishikawa cells, vehicle control; (D) progestin-resistant Ishikawa cells, MPA. MPA, medroxyprogesterone acetate.