GDNF and non-small cell lung carcinoma: Other studies hold the view that SULFs are positive regulators of oncogenetic signaling pathways, including Wnt, BMP, Hedgehog and GDNF [14]–[16], and increased expression of SULFs is prevalent in various cancers, including gastric, hepatocellular, pancreatic and breast cancers, non-small cell lung cancer (NSCLC) and head and neck tumors [10], [13], [17]–[20].