KRAS and serous cystadenoma: Prior studies that have supported this model by showing (1) serous borderline tumors and in adjacent serous cystadenoma epithelia are present similar mutations of KRAS and BRAF genes [34]; (2) OEIs from ovaries with serous borderline tumors have higher levels of epithelial cell aneusomy than that of OEIs from ovaries with nonneoplastic disease [35]; and (3) a strong relationship between LGSC and serous borderline tumors has been reported previously [36].