PTK7 and cancer: PTK7 acts as both an inhibitor of canonical WNTsignaling and as activator of WNT-PCP signaling, and its upregulationresults in increased cell motility, migration, and metastasis.82−84 In addition, PCP pathway activation leads to activation of YAP/TAZsignaling, which results in a pro-migratory metastatic phenotype thatis crucial for liver colonization by CRC cells.85,86 Concomitantly, YAP/TAZ activation leads to the increased secretionof WNT inhibitors by cancer cells.