Our mechanistic studies demonstrate that miR-550a-3p exerts its tumor-suppressor role by directly targeting and repressing ERK1 and ERK2 and thereby suppresses the oncogenic ERK/RSK cascades [5, 34], reducing breast cancer cell viability, survival, migration, invasion, tumorigenesis, and metastasis (Figure 8). The gene discussed is MAPK1; the disease is breast carcinoma.