RAP1B and neoplasm: RAP1B is mainly located in the nucleus, and studies have shown that RAP1B expression is associated with tumorigenesis and metastasis in, for example, ovarian cancer, oesophageal squamous cell carcinoma, and gastric cancer, and can act as a tumour promoter by regulating multiple signalling pathways such as Wnt/β‐catenin, PI3K/AKT/mTOR pathway.18, 19, 20, 21, 22