PKD1 and cancer: PKD1 negatively regulates cancer cell motility through multiple mechanisms including inactivating transcription factor Snail [74,75], phosphorylating adherens junctional proteins (E-cadherin and β-catenin) [76,77] and metastasis-associated protein 1 (MTA1) [78], regulating integrin trafficking [79], stabilizing F-actin filaments at leading edges and filopodia [81,88,124,125,126,128], and repressing the expression of MMPs [80].