Purpose of investigation: We have studied by immunohistochemistry the presence and localization of CD44, estrogen and progesterone receptors, p53 and proliferative associated indices (MIB1, PCNA) in archival endometrial tissue, in order to determine their diagnostic and prognostic value as well as the possible correlations between them.
Methods: We examined 186 samples of endometrial tissue (100 endometrial carcinomas of endometrioid type, 40 cases of hyperplasia and 46 of normal endometrium). Patient records were examined for FIGO stage, grade, and depth of myometrial invasion, histology, and lympho-vascular space invasion.
Results: Strong membranous immunostaining (> 10% of neoplastic cells) was observed in 45% of the carcinomas. A statistically significant correlation was found in the expression of protein in stromal cells, when compared with epithelial cells (p < 0.0001). Immunohistochemical expression of CD44 was significantly lower in cancer cases than in normal endometrium, mainly in the secretory phase (p < 0.0001). CD44 positive cases by immunohistochemistry failed to show any statistical correlation with tumor grade or with vessel invasion. The expression of the protein was lower in FIGO Stage II compared with Stage I (p = 0.03). A positive relation of CD44 expression with progesterone receptor status (p = 0.02) was detected. CD44 expression was also positively associated with the proliferation associated with the proliferative index MIB1 (p = 0.001).
Conclusion: CD44 is closely related to the secretory phase of the normal menstrual cycle and its expression is decreased in hyperplasia (simple or complex with or without atypia) and in cancer cases. These observations suggest that decreased CD44 expression might be functionally involved in the multiple mechanisms of the development and progression of endometrial lesions.