PFN1 and breast carcinoma: Post-translational modification such as phosphorylation can alter the function of cytoskeletal-associated proteins in tumorigenesis; since profilin 1 is known to undergo phosphorylation at Ser137 preferentially by PKCζ, an enzyme with potential role in breast cancer cell chemotaxis and tumor invasion [31]–[33]; we also examined PKCζ levels by western blotting in breast cancer and adjacent normal tissues (Figure 1A, middle panel).