The expression of functional factors CXCL13 and IL-21 decreased gradually in higher tumor stages (Figure 1K), although the proportion of tumor-infiltrating Tfh cells among CD4+ T cells showed no significant reduction (Figure 1J), which suggested that the function of Tfh cells was impaired in the tumor microenvironment of PDAC. This evidence concerns the gene CXCL13 and neoplasm.