PCBP1 and carcinoma: Our previous studies have shown that multiple intracellular functions of PCBP1 participate in carcinoma progression.4–6 Studies by our group and others have shown that PCBP1 suppresses epithelial-to-mesenchymal transition (EMT) in mammary epithelium and that it also acts as a master regulator of epithelial cell polarity and differentiation status.5,7–10 Loss of PCBP1 function in normal murine mammary gland (NMuMG) cells confers an invasive, migratory phenotype that initiates tumors.