STAT3 and neoplasm: The anti-tumor effects of Ex-4 were associated with high expression of GLP-1R and activation of cAMP and protein kinase A (PKA), while Ex-4 further inhibited the expression of epidermal growth factor receptor (EGFR) and signal transducer and activator of transcription 3 (STAT3), which lie downstream of cAMP-PKA signaling, leading to the suppression of multiple STAT3-targeted genes, amongst which were c-Myc, cyclin D1, survivin, Bcl-2 and Bcl-xl.