GAS6 and Patent ductus arteriosus: In the digestive system, Gas6 is involved in OSCC, gastric cancer, PDA, intestinal tumours and hepatocellular carcinoma.8, 13, 15, 84, 85, 86 Gas6/Axl is detected in OSCC, and Axl can be a prognostic marker for OSCC.13 Jiang et al.87 explored the level and clinical significance of serum Gas6 in patients with OSCC and found that Gas6 increases the metastatic capacity of OSCC cells and that serum Gas6 could be a biomarker for diagnostic and prognostic use in OSCC patients.