As another example, plasma exosomal circ-133 can be used as a biomarker to monitor colorectal tumor progression, as exosomal circ-133 expression induced by hypoxia was able to sponge miR-133a to activate the GEF-H1/RhoA axis in normoxic colorectal cancer cells, leading to the migration of colorectal cancer cells [141]. This evidence concerns the gene ARHGEF2 and colorectal cancer.