A peptide cancer vaccine comprised of four peptide chains derived from the Wilms' tumor gene 1 (WT1) protein, with potential immunomodulating and antineoplastic activities. Upon administration, galinpepimut-S, which is comprised of one WT1-derived peptide (WT-A1) that may stimulate CD8-positive T-cell responses; two WT1 peptides (WT1-427 long, WT1-331 long) that may stimulate CD4-positive T-cell responses; and one modified peptide (WT1-122A1 long) that may stimulate both CD4-positive and CD8-positive T-cells, may elicit a targeted innate immune response against WT1-expressing tumor cells. WT1 protein, a zinc finger DNA-binding protein and transcription factor, is overexpressed in leukemic cells and in many non-hematological solid tumors. [ ]