Provided are novel MUC1 peptides for use in anti-tumor vaccination and methods of producing those peptides. Furthermore, methods of producing a population of autologous antigen presenting cells (APCs) and of producing genetically engineered APCs, which are capable of inducing effective immune responses against MUC1 are described. The described peptides are particularly useful for the treatment of breast cancer or other MUC1-positive carcinomas including colorectal, pancreatic and gastric carcinomas.