PKD2 and breast cancer: For example, NRAS, a well‐characterized oncogene, was downregulated upon silencing PKD2 and silencing both PKD2 and PKD3, but not suppressed when silencing PKD3 in both MDA‐MB‐231 and MDA‐MB‐468 cells (Figure 4D), which suggested differentially regulatory roles of PKD2 and PKD3 in breast cancer.