P4HA1 and colorectal carcinoma: Furthermore, P4HA1 is highly expressed in CRC tissues and cells, and knocking down P4HA1 inhibits CRC cell proliferation, induces cell cycle arrest at the G0/G1 phase, decreases CRC cell stemness, reduces tumor sphere formation and size, lowers CRC cell chemoresistance, and increases Caspase-3 activity [36].