Upregulated neuropeptide genes, such as PTHLH, Gastrin (GAST), Secretogranin V (SCG5), Neuromedin B (NMB), and Apelin (APLN), were positively correlated with upregulated neurotrophic factors, which were consistent with their roles in tumor progression and neuroimmune crosstalk. This evidence concerns the gene APLN and neoplasm.