RET and gastric cancer: Apart from the PI3K/AKT pathway, CNTN1 is also associated with the RhoA pathway in gastric cancer; VEGF-C/VEGFR-3 pathway in lung, gastric, and esophageal cancers, and OSCC; α7 nAChR/ERK and Src-p38 MAPK-C/EBPα pathways in lung cancer; and Notch1 and RET/PTC3 pathways in thyroid cancer.