CD44 and cholangiocarcinoma: This study has demonstrated that CCA organoids have cancer stem cell-like characteristics, such as high expression of Cd24, Cd44, and Sca1, as well as the ability to generate secondary tumors when transplanted in mice; however, the same cells cultured in 2D monolayers have decreased successful rates to generate CCA tumors after transplantation into syngeneic mice, indicating that organoids may be a better technique to retain CCA cell functions in vitro compared to classic monolayer cultures [59].