Specifically, PB samples from six HLA-A*02:01-positive NPM1-mutated AML patients were analyzed for immune responses against CLAVEEVSL, but tetramer-positive T cells were not detected, possibly indicating that frequencies of specific immune response naturally occurring in vivo in these patients having achieved complete remission (CR) after chemotherapy, could be below the threshold of detection. The gene discussed is NPM1; the disease is acute myeloid leukemia.