MMP9 and neoplasm: Some studies also point out that the expressions of immunohistochemical biomarkers of Ki-67 and MMP-9, which are associated with tumor proliferation and invasion, are positive in GCOC.[36] As a result of the high levels of expression of those biomarkers, Ki-67 and MMP-9 can be helpful in the diagnosis and evaluation of the prognosis of GCOC.[6,11] In short, the pathologists should pay more attention to these histopathological features and provide the accurate pathology reports, which is important to the clinical doctors.