EPCAM and malignant colon neoplasm: These observations and the fact that over 80% of colonospheres-derived cells are CD44 positive, a widely accepted colon CSC marker, and that the cells of colonospheres also show staining of EpCAM, which is believed to be a putative CSC marker in colon cancer cell lines, strongly indicate that colonospheres generated under present conditions are mainly composed of CSCs.