The immunological profile of tumor-bearing animals determines the outcome of cancer immunotherapy

Do cancer patients responding to immunotherapy have immunological profiles that influence the therapeutic outcome, or do they develop efficient antitumor responses only upon immunotherapy? We came across this “chicken or the egg” dilemma when treating secondary liver tumors with Semliki Forest viruses expressing interleukin-12. In our system, the “egg,” that is, the pre-treatment immunological profile, seemed to make the difference. The properties of an effective antitumor response were also defined.