We developed an in vitro stimulation approach and identified HLA-A*11:01–restricted KRAS G12V–reactive CD8+ T cells and HLA-DRB1*15:01–restricted KRAS G12V–reactive CD4+ T cells from peripheral blood of 2 out of 6 HLA-A*11:01–positive patients with pancreatic cancer whose tumors expressed KRAS G12V. This evidence concerns the gene CD4 and familial pancreatic carcinoma.