Expression of estrogen receptor, progesterone receptor, WT1, and Ki-67 in ovarian and endometrial serous carcinoma histopathology and peritoneal fluid

Background: Serous carcinomas are one of the most virulent cancers throughout the world. They can originate from ovary, endometrium, tube, or peritoneal cavity. A combination of immunohistochemical (IHC) markers is necessary to distinguish the primary origin of serous carcinoma, as they have prognostic and therapeutic implications. Aims and Objectives: We have studied the expression of estrogen receptor (ER), progesterone receptor (PR), WT1, and Ki-67 markers in ovarian and endometrial serous carcinomas (ESCs). Materials and Methods: Patients undergoing hysterectomy for ovarian or uterine mass detected radiologically or by previous small biopsy were evaluated. Histopathological examination and IHC were done. Results: Among 50 cases, 46 cases were ovarian serous carcinoma (OSC) and 4 cases were ESC. From 46 OSC cases, 7 cases were low-grade OSC (LGOSC) and 39 cases were high-grade OSC (HGOSC). Mean age of presentation for HGOSC is 51.6±10.8 years, 48.85±7.8 years for LGOSC, and 68±1.6 years for ESC. ER was positive in 78% of OSC and negative in 100% ESC. All LGOSC cases were ER negative and 72% cases of HGOSC cases were ER positive. PR universally stained ESC, but only 65% of OSC. PR comparatively better stained LGOSC cases than HGOSC. Almost all OSC cases stained with WT1 but almost none of ESC cases. WT1 failed to differentiate HGOSC versus LGOSC cases. Ki-67 was high in all cases of ESC and most cases of OSC. Conclusion: Ki-67 can be used to distinguish low-grade from high-grade serous carcinoma. ER and WT1 can be used to differentiate the endometrial versus ovarian origin of serous carcinoma.