Since mdig is transcriptionally governed by an upstream regulator c-myc (210), which has both tumor accelerator and suppressive roles and can inhibit cancer metastasis (211), our studies are suggestive of the dual roles of mdig in breast cancer, where it is essential for the early stages of cancer development due to its pro-proliferative feature but is inhibitory in the later stages owing to its metastasis inhibitory features. The gene discussed is RIOX2; the disease is breast cancer.