1. A method of treating cancer in a subject identified as having MHC class II expressing tumor cells undergoing autophagy, wherein the autophagy comprises peptidylarginine deiminase 2 (PAD2) or peptidylarginine deiminase 4 (PAD4) enzyme-mediated production of self-epitopes having a modification of deimination of arginine to citrulline, wherein the resulting self-epitopes are presented on the surface of the tumor cells via MHC class II complexes, the method comprising administering to the subject a composition that comprises a Th1 adjuvant and peptides comprising at least one of the self-epitopes in an amount effective to induce IFN-γ and granzyme B-secreting CD4 T-cells that bind the MHC class II complexes presented on the surface of the tumor cells.