MUC1 is an antigen that is overexpressed on the cell surface of many human breast adenocarcinomas and other types of cancer. The cancer immunity cycle has seven steps, starting with release of cancer cell antigen and following with cancer antigen presentation. Priming, activation and trafficking of T cells to tumors are the next steps and the infiltration of T cells into tumors, the recognition of cancer cells by T cells and killing of cancer cells are the final steps. We have tested a synthetic peptide for the MUC1 antigen and generated dendritic cells (DCs) that were pulsed with the specific peptide. Mature DCs were used to activate naive T cells to differentiate into antigen-specific CTLs. CTLs were tested for proliferation, cytokine release (IFNγ), activation markers and cytotoxicity against human breast adenocarcinoma cell lines. The cytotoxic effect of those CTLs was higher against MCF7 human cell line than against MDA-MB-231 human cell line.