Glycodelin (Gd), previously known as placental protein 14 (PP 14), acts as an immuno-suppressive glycoprotein by suppressing the cytolytic capacity of human natural killer (NK) cells and T-cells in vitro. Glycodelin is expressed in normal glandular epithelium of the endometrium as well as in normal and malignant glandular cells in and outside of the reproductive tract. Recently, Gd expression was demonstrated in normal and cancerous human breast tissue. Paraffin-embedded breast cancer tissue blocks (n=121) were examined for Gd expression. No part of the specimens contained carcinoma in situ. Gd expression was present in lobular and ductal breast carcinoma. We observed expression of Gd in breast cancer independent of grading. With regard to nodal status, no significant differences in the expression of Gd between cancer tissue from patients with or without axillary lymph node metastases were present. However, Gd expression was found to be significantly higher in breast cancer tissue when the staining reaction for steroid receptors was also positive. These results implicate that Gd might be an additional marker for the differentiation of breast cancer tissue. To which extent Gd could serve as an additional indicator for breast cancer survival is part of our ongoing research.