Consistently, we performed a siRNA-based knockdown experiment in SK-MES-1 lung cancer cells, where NEDD4-1 levels are high, but SAG levels are moderate, and found that the endogenous SAG level increased when NEDD4-1 was knocked down by two independent siRNAs in a manner dependent on the level of NEDD4-1 knockdown (Figure 4E). Here, SAG is linked to lung cancer.