The purpose of the present invention is to provide a method of purification and preparation of cultured corneal endothelial cells, and in particular, to provide cell surface markers for use in corneal endothelial cells not including transformed cells. Provided are cell markers for distinguishing normal cells and transformed cells, in particular normal and transformed corneal endothelium cells. These cell markers relate to specific cell surface markers, for example, to a normal corneal endothelial surface marker such as CD166, and a transformed cell surface marker such as CD73. By using the transformed cell surface marker such as CD73 to remove transformed cells by sorting, it becomes possible to improve purity of a normal cultured corneal endothelium. By using normal corneal endothelial surface marker such as CD166, or by combined use with the transformed cell surface marker, it becomes possible to provide a means for verifying the purity of a prepared corneal endothelium.
