In the current review, an attempt to clarify the principles of both onset and development of full-scale antitumor immune response upon in situ vaccination, which is a new trend in anticancer immunotherapy, has been done. Modern methods of cancer immunotherapy usually require the presence of a specific target antigen. The in situ vaccination approach does not require a specific antigen. The whole set of determinants necessary for the formation of the immune response appears in the vaccination site as a result of lysis of tumor cells by cells of innate immunity, infiltrating the tumor and activated as a result of the treatments.

The first part of the review is a compilation of known findings, which are peculiarly composed to give the clear understanding of causes, circumstances and factors determining the appearance in the local tumor node of a totality of tumor antigens essential for the development of an adaptive antitumor immune response. In the second part of the review, possible events of antitumor immune response development upon in situ vaccination with use of ligand-receptor interaction and antigen-presenting cells activation are being analyzed within the confines of a previously given data composition.