CD44 and breast carcinoma: To identify the neurogenes differentially expressed between breast cancer CD44+ population and the more differentiated CD44-CD24+ (hereinafter referred to as CD24+) cells, we used the databases containing the Serial Analysis of Gene Expression (SAGE) expression libraries obtained in the laboratory of Dr. Kornelia Polyak (in collaboration with Dr. Kornelia Polyak, for more details on the procedure see Shipitsin, M. et al [40]).