PJA1 and breast cancer: It has been reported that TRIM28 promotes proliferation and metastatic progression of breast cancer and associates with aggressive clinical features in gastric, non-small cell lung cancer and pancreatic cancer.31, 32, 33 Although MAGE proteins are normally expressed only in the testis, they are aberrantly re-expressed in cancerous tissues.34, 35 MAGE proteins bind with specific RING proteins to form MAGE-RING complexes in cells, including MAGE-C2-TRIM28, MAGE-A3/6-TRIM28 and MAGE-D1-Praja-1.9 Furthermore, each MAGE protein binds to a specific RING protein through the MHD domain.