STAT1 and colorectal carcinoma: Therefore, PD-L1 expression is regulated by the JAK-STAT1 signaling axis in CRC cells, and the qPCR results suggest that P4HA2 regulates the PD-L1 axis and that PD-L1 is a STAT1 transcriptional target regulated by P4HA2 to facilitate eventual immune evasion.