MAPK3 and endometrium adenocarcinoma: As the key effector molecules on MEK/ERK pathway, the staining of ERK1/2 and p-ERK1/2 was predominantly located in the cytoplasm and nuclear of tumor cells, and they were both over-expressed in endometrial adenocarcinoma compared to normal endometrium (p = 4.19E− 10, p = 2.77E− 8) and atypical endometrial hyperplasia tissues (p = 1.97E− 7, p = 0.036) (Table.1).