What is clear from these studies is that there is enormous variation in the types of cancer treated, combined with heterogeneity in the protocols used to expand γδ T cells in vivo or ex vivo for cellular immunotherapy, or in how the immunotherapy was delivered (e.g., PAgs or Zoledronate with or without IL-2, or in combination with other drugs, γδ T cells alone or in combination with activating drugs such as IL-2 and Zoledronate). This evidence concerns the gene IL2 and cancer.