Corneal epithelial stem cells (CESCs) are essential for maintaining the ocular surface. However, the lack of surface markers for CESCs remains a serious obstacle in the identification of CESCs. Previously, we showed that rabbit limbal epithelial side population (rLE-SP) cells exhibited stem cell phenotypes including increased expression of CD61, a marker for mouse hematopoietic stem cells. Here, we demonstrate that nectin-3, an immunoglobulin-like cell-cell adhesion molecule, is highly expressed in rLE-SP cells. Additionally, nectin-3(+) cells were significantly enriched among CD61(+)rLE-SP cells as compared to CD61(-)rLE-SP cells. In mouse bone marrow side population cells, a correlation between expression of nectin-3 and CD61 was also observed. These data strongly suggest that nectin-3 may contribute to the identification of CESCs. (C) 2009 Elsevier Inc. All rights reserved.