Prognostic and Therapeutic Role of CD15 and CD15s in Cancer

SIMPLE SUMMARY: CD15 (Lewis X) is a typical myeloid antigen presented in myeloid and monocytic lineages of cells. This molecule interacts with E-, L- and P-selectins, which allows for adhesion with endothelial cells. CD15 is found on various cancer cells, including renal cancer, prostate and bladder cancers, acute leukaemias, hepatocellular carcinoma, breast cancer and melanoma cells. Its high expression can serve as a prognostic marker for patients and is a potentially valuable target for immunotherapy against cancer. Blockage of the antigen’s function results in reduced metastatic potential and it may be an immunotherapeutic target. CD15s is a sialyl derivative of CD15; however, unlike the high expression of CD15, which is a prognostic factor in Hodgkin lymphoma, CD15s relates to poor prognosis for patients. CD15 is considered a marker of cancer stem cells. This review presents a comprehensive description of the prognostic role of CD15 and CD15s and their use in anticancer therapy. ABSTRACT: CD15 (Lewis X/Lex) is a fucosyl (3-fucosly-N-acetyl-lactosamine) moiety found on membrane proteins of various cancer cells. These cancers include renal cancer, prostate and bladder cancers, acute leukaemias, hepatocellular carcinoma, breast cancer and melanoma. The biological role of CD15 is interaction with E-, L- and P-selectins (adhesion molecules), allowing for adhesion with endothelial cells. In this way, cancer cells start to interact with the endothelia of blood vessels and consequently move out from the blood flow to the surrounding tissues. Blockage of the antigen’s function results in reduced metastatic potential. Moreover, the molecule may be a therapeutic target against cancer in monoclonal antibody-based therapies. CD15 may serve as a prognostic marker for patients and there are high hopes for its use in the immunotherapeutic treatment of tumours. CD15s is a sialyl derivative of CD15 that possesses its own unique characteristics. Its soluble form may act as a competitive inhibitor of the interaction of cancer cells with epithelial cells and thus disallow migration through the vessels. However, the prognostic relevance of CD15 and CD15s expression is very complex. This review presents a comprehensive description of the role of CD15 and CD15s in cancer development and metastasis and overviews its significance for clinical applications.