CD44 and breast cancer: To begin to analyze the potential role of sGRP78 expression in stemness in cancer, we performed experiments with the breast cancer cell lines MCF7 (luminal A subtype25) and MDA-MB-231 (basal subtype25) that contain low or high levels of previously defined CD24−/CD44+ tumor initiating cells (TICs) respectively, a cell population with breast cancer cells shown to be able to generate tumors with much higher efficiency in in vivo xenograft transplantation assays26.