For example, aggressive invasion is a feature of placental site tumours, such as choriocarcinoma,36, 37 whereas shallow invasion is characteristic of PE.35 Many studies have suggested that trophoblasts are very similar in nature to tumour cells primarily based on the proliferative and invasive properties of these two cell types,19, 20 and EPCR is highly expressed in various malignancies and is involved in tumour cell proliferation, invasion, metastasis and apoptosis.38, 39, 40 However, the role of EPCR in trophoblasts and PE is not clear. This evidence concerns the gene PROCR and neoplasm.