However, we observed that the frequencies of naïve T cells (including CD4 + and CD8 +) in cancer donors were much lower than that of healthy individuals, and the frequencies of Tregs were substantially higher in most cancer donors (Fig. 4b-c, and Additional file 1: Fig. S9a-c), especially in pancreatic cancer donors. This evidence concerns the gene CD8A and familial pancreatic carcinoma.