PTK2 and renal cell carcinoma: By Western blot analysis, we found that relative to vector control, transfection with PLCD1 plasmid reduced the levels of p-EGFR, p-Src, p-FAK (Tyr397) and p-ERK, but did not significantly change the level of their total proteins (Fig. 6e), demonstrating that PLCD1 negatively regulates EGFR-FAK-ERK signaling in RCC cells.