He et al. constructed a recombinant Bacillus Calmette Guérin (rBCG)-MUC1-interleukin-2 (IL-2), and in vivo experiments showed that rBCG-MUC1-IL2 can preferentially induce MUC1-specific cellular immune responses and can be used as a vaccine for the prevention and treatment of breast cancer [40]. Here, IL2 is linked to breast cancer.