SERPINB5 and cancer: The analogy between early placentation and malignant tumors at the epigenetic level is further stressed by studies analyzing the methylation status of the promoters of several tumor suppressor genes (RASSF1A, SERPINB5 also known as APC and Maspin, respectively) in the developing placenta and human choriocarcinoma cell lines (JAR and JEG3) [25,49].