ABSTRACT: Translation of the noncoding genome in cancer can generate cryptic (noncanonical) peptides capable of presentation by human leukocyte antigen class I (HLA-I); however, the cancer specificity and immunogenicity of noncanonical HLA-I-bound peptides (ncHLAp) are incompletely understood. Using high-resolution immunopeptidomics, we discovered that cryptic peptides are abundant in the pancreatic cancer immunopeptidome. Approximately 30% of ncHLAp exhibited cancer-restricted translation, and a substantial subset were shared among patients. Cancer-restricted ncHLAp displayed robust immunogenic potential in a sensitive ex vivo T cell priming platform. ncHLAp-reactive, T cell receptor-redirected T cells exhibited tumoricidal activity against patient-derived pancreatic cancer organoids. These findings demonstrate that pancreatic cancer harbors cancer-restricted ncHLAp that can be recognized by cytotoxic T cells. Future therapeutic strategies for pancreatic cancer, and potentially other solid tumors, may include targeting cryptic antigens.
Author Info: (1) Koch Institute at MIT, Cambridge, MA, USA. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA. (2) Koch Institute at MIT, Cambridge, MA, USA. Dana

Author Info: (1) Koch Institute at MIT, Cambridge, MA, USA. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA. (2) Koch Institute at MIT, Cambridge, MA, USA. Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (3) Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. Harvard Medical School, Boston, MA, USA. (4) Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (5) The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (6) Dana-Farber Cancer Institute, Boston, MA, USA. (7) The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (8) Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (9) The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (10) Dana-Farber Cancer Institute, Boston, MA, USA. (11) Program in Immunology, Fred Hutchinson Cancer Center, Seattle, WA, USA. (12) Dana-Farber Cancer Institute, Boston, MA, USA. (13) Koch Institute at MIT, Cambridge, MA, USA. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA. (14) Dana-Farber Cancer Institute, Boston, MA, USA. (15) Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. Hale Family Center for Pancreatic Cancer Research at DFCI, Boston, MA, USA. (16) Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark. (17) The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (18) Koch Institute at MIT, Cambridge, MA, USA. (19) Koch Institute at MIT, Cambridge, MA, USA. (20) Dana-Farber Cancer Institute, Boston, MA, USA. Harvard Medical School, Boston, MA, USA. Hale Family Center for Pancreatic Cancer Research at DFCI, Boston, MA, USA. (21) Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. Harvard Medical School, Boston, MA, USA. Hale Family Center for Pancreatic Cancer Research at DFCI, Boston, MA, USA. (22) Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. Harvard Medical School, Boston, MA, USA. (23) Program in Immunology, Fred Hutchinson Cancer Center, Seattle, WA, USA. Division of Medical Oncology, Department of Medicine, University of Washington, Seattle, WA, USA. Department of Immunology, University of Washington, Seattle, WA, USA. (24) Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. Harvard Medical School, Boston, MA, USA. Hale Family Center for Pancreatic Cancer Research at DFCI, Boston, MA, USA. (25) Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (26) The Broad Institute of MIT and Harvard, Cambridge, MA, USA. (27) Koch Institute at MIT, Cambridge, MA, USA. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA. (28) Koch Institute at MIT, Cambridge, MA, USA. Dana-Farber Cancer Institute, Boston, MA, USA. The Broad Institute of MIT and Harvard, Cambridge, MA, USA. Harvard Medical School, Boston, MA, USA. Hale Family Center for Pancreatic Cancer Research at DFCI, Boston, MA, USA.
