Epithelial versus endothelial CEACAM1 expression and angiogenesis in epididymal adenomatoid tumor

To study the expression of the pro-angiogenic factor carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM1) in epididymal adeno-matoid tumor tissue, a very rare benign neoplasia, in relation to its vascularization.

Immunohistochemistry for CEACAM1 and for both endothelial markers CD31 and CD34 was performed in normal human epididymal and epididymal adenomatoid tumor tissue. The vessel density was calculated in four tumor regions with different degrees of vascularization in comparison to the vascularization of the normal epididymal tissue.

CEACAM1 was found in normal epididymal epithelium, while the epithelium of tumor glands was mostly negative. Only few blood vessels and lymphatics in adenomatoid tumor tissue expressed CEACAM1. The assessment of vascularization revealed either equal or a significantly lower vessel density in some adenomatoid tumor regions in comparison to normal epididymal tissue.

These data demonstrate that despite its epithelial down-regulation, CEACAM1 is not present in the majority of adenomatoid tumor blood vessels, which might be related to the lower angiogenic activity and benign behaviour of this tumor.