The numbers of CD8+ and CD4+ T cells were not statistically different between pNECs and ESCC (CD8+ T cells: 1202/mm2 vs. 1143/mm2, p = 0.872; CD4+ T cells: 1549/mm2 vs. 2872/mm2, p = 0.06, see Figure 7B). Here, CD4 is linked to esophageal squamous cell carcinoma.