PNPO and cancer: Furthermore, we also found that the expression of PNPO was significantly correlated with the immune-associated cell infiltration levels of macrophages in 9 cancer types, CD4+T cells in 4 cancer types, dendritic cells in 3 cancer types, mast cells in 3 cancer types, and CD8+T cells in 3 cancer types in the ESTIMATE algorithm (Figure 6).