Immunohistochemical determination of the expression of Eph receptors in lipid-rich variation of experimental rat mammary carcinomas.

Lipid-rich breast carcinomas are one type of invasive carcinoma. Receptor tyrosine kinases play a critical role in regulating the metabolism of cancer cells. Erythropoietin-producing hepatocellular carcinoma (Eph) receptor signaling systems have distinct functions in the various cell types comprising tumors and mediate reciprocal communication between tumor cells and their microenvironment. This study aimed to evaluate the overall prognostic immunohistochemical features and expression of three different erythropoietin-producing hepatocellular carcinoma receptors in breast cancer induced by chemical carcinogenesis. In this experimental study, mammary tumors were induced by oral gavage administration of 20 mg 7,12-dimethylbenz[a]anthracene (DMBA) to female Sprague-Dawley rats. Hematoxylin and eosin, Periodic Acid-Schiff, and oil-red-O staining were performed to determine whether the vacuolated degenerated cells contained glycogen or lipid droplets. Subsequently, immunohistochemical analyses were performed, and the malignancy and immunohistochemical characteristics were evaluated. Eleven of the 24 animals with tumors were classified as lipid-rich carcinoma of rats and immunohistochemically, it was negative for anti-ER and PR antibodies and weakly HER2/neu-positive. The expression of erythropoietin-producing hepatocellular carcinoma receptors was also evaluated, revealing weak expression of EphB3, whereas EphB6 and EphA4 showed stronger expression. These findings contribute to a better understanding of the biological characteristics of lipid-rich breast carcinomas, particularly regarding their high lipid metabolic activity.