MKI67 and endometrioid stromal sarcoma: Using survival analysis, the prognostic value of classical mitosis counts (Mitotic Activity Index, MAI) in haematoxyllin-eosin (H&E) sections, and immunohistochemical proliferation biomarkers (Ki-67 and PhosphoHistone-3 (PPH3)) were examined in 24 invasive endometrial stromal sarcomas.