The expression levels of COL9A3, ASPN, ESR1, MUC1, PIP, SFRP4, KRT19, CLDN1, and COMP were significantly higher in tumor tissues of patients with the PNI group compared to those in the non-PNI group (q < 0.05), as shown in Figure 2. This evidence concerns the gene CLDN1 and neoplasm.