GCG and cancer: KEGG analysis revealed that the proteins in cluster 3 were mainly associated with the nervous and endocrine systems (dopaminergic synapse, insulin, glucagon, adrenergic, prolactin, and oxytocin), signal transduction (MAPK, Hippo, and calcium signaling pathways), and immunity and disease (T cell receptor signaling pathway, microRNAs in cancer, viral carcinogenesis, etc.; Figure 3).