Tissue HE4 Expression Discriminates the Ovarian Serous Carcinoma but Not the Uterine Serous Carcinoma Patients. A New Adjunct to the Origin of the Tumor Site

Both uterine serous carcinoma (USC) and ovarian serous carcinoma (OSC) are presented at advanced stage at the first admittion and dissseminated disease makes the anatomical site of the tumor origin imposible. CA125 and p53 are reliable markers that are useful for differentiating both uterine serous and ovarian serous carcinoma from their most common subtypes (endometrioid type carcinoma of ovary and uterus) but so far there is no histopathologic marker that differentiates USC from OSC. On the other hand, Trastuzumab (Herceptin) increases progression-free survival among USC patients, but not OSC patients and makes the histopathologically assigning the origin of the tumor important. So, the aim of this study was to evaluate the immunohistopathological discriminative value of the human epididymis secretory protein 4 (HE4) between OSC and USC patients. Patients with a diagnosis of OSC and UTC were enrolled. HE4 expression was evaluated by immunohistochemistry. The results were compared between groups. Of the tumor tissues studied, HE4 immunostaining was seen in the majority of ovarian serous carcinoma cases (89.65%), while endomatrial serous carcinoma cases were devoid of HE4 immunostaining. HE4 immunostaining was seen in 39.1% uterin serous carcinoma cases and this difference was statistically significant (p = 0.001). Our study demonstrated for the first time the potential of HE4 expression to predict the anatomical site of tumor origin. HE4 is a novel tumor marker that differentiates USC from OSC.