Background: Sialyl Lewis x (SLeX), sialyl Lewis a (SLeA), Lewis Y (LeY) and the Thomsen-Friedenreich (TF) antigen are carbohydrate motifs that mediate the adhesion between tumour cells and the endothelium. These antigens are usually not expressed in non-malignant tissue. Overexpression of SLeX and SLeA is combined with poor prognosis and malignant relapse. In this study, we analysed the combined expression of SLeX, SLeA, LeY and TF in normal squamous epithelium tissue of the penis shaft, glans and foreskin and in addition of the vagina and vulva.
Materials and methods: Paraffin-embedded slides of vaginal tissue (8), vulva tissue (8) and penis shaft (8) and glans tissue (8) were fixed and incubated with monoclonal antibodies against SLeX (IgM), SLeA (IgM), LeY (IgM) and TF (IgM). Staining reaction was performed with ABC reagent. The intensity of immunohistochemical reaction on images of the slides was analyzed using a semiquantitative score.
Results: Strong focal expression of both sialyl Lewis antigens was found in the uretra of the penis shaft and on epithelial tissue of the glans, and permanent moderate expression of SLeX and SLeA in squamous epithelial tissue of the vagina. Moderate expression of TF was observed in male squamous epithelial tissues of the glans and foreskin and faint expression of TF was found in vulval epithelial tissue. Faint expression of Le Y was observed in female vulval epithelial tissue.
Conclusion: Expression of SLeX, SLeA, LeY and especially of the TF antigen in normal non malignant epithelial tissue is surprising and can be explained by the function of this tissue in human reproduction. In addition, moderate TF expression seems to be restricted to epithelial tissue of the penis glans and foreskin.