Immunohistological localization of tenascin in the human endometrium

Tenascin (TN) is an extracellular matrix glycoprotein that seems to be involved in embryogenesis, carcinogenesis and wound healing. In order to clarify the biological significance of TN in the human endometrium, we investigated its expression in the normal as well as in the hyperplastic and neoplastic human endometrium, using immunohistochemistry. We also investigated the coexistence of TN with proliferating cell nuclear antigen (PCNA), a marker of cell proliferation, in endometrial carcinoma to further assess the involvement of TN in regulating cell proliferation. TN expression was observed in the stroma surrounding the endometrial gland in the proliferative phase, whereas it could not be found in the secretory phase. The localization of TN and PCNA coincided frequently, as the stromal portion where the expression of TN was observed always showed positive for PCNA. These results suggest that TN is involved in cell proliferation and carcinogenesis in the human endometrium.