The invention concerns a method of preparing a composition comprising stimulated immune system cells such as dendritic cells (DC) for use in inducing immune response of cytotoxic T lymphocytes against colorectal cancer. The dendritic cells are pulsed by contact with colorectal cancer stem cells (CSC) or their fragments thereof. These colorectal CSCs are produced by OSKM (Oct4, Sox2, Klf4 and c-Myc) induced reprogramming of differentiated colorectal cancer cells (CRC) which results in undifferentiated colorectal CSC-like cells. Both the CSC-like cells and the lysates of heat-shocked CSC-like cells could be used as an accessible source of tumour antigens for DC pulsing to induce specific immune responses against colorectal CSCs.
