KRT18 and prostate cancer: SPDEF has been previously shown to act as a negative regulator of tumor progression and to elicit its metastasis suppressor function by regulating a gene expression program linked to maintaining the epithelial phenotype, while knock down of SPDEF induces EMT by reducing expression of epithelial-specific genes such as E-cadherin and cytokeratin 18 and enhancing expression of mesenchymal genes that promote prostate cancer migration, invasion and metastasis [5, 13-15, 25].