RAP1B and colorectal carcinoma: RAP1B, a Ras-related small GTP-binding protein that behaves as a GTPase, has been implicated as an oncogene in a variety of tumors, including esophageal squamous cell carcinoma (ESCC), CRC, T-acute lymphoblastic leukemia, non-small cell lung carcinoma, glioma and thyroid carcinoma [19–27].