CD44 and ovarian cancer: Here, we compared the CSC properties of primary ovarian tumour and ascites-derived tumour cells, and subsequently analysed CSC properties, metabolic switches and PDK4 expression in spheroid cells (tumourspheres) and in the ALDH+CD44+ subset derived from ascites and ascites-originating ovarian cancer cell lines versus monolayer cells and the ALDH−CD44− subset.