Although we have shown that EWS-Oct-4B regulates the expression of fgf-4 and nanog, which are known potent mitogens (Figure 7), it remains to be seen whether the activation of fgf-4 or nanog through EWS-Oct-4B is sufficient to produce the neoplastic phenotype found in the two types of epithelial tumours, hidradenoma of the skin and mucoepidermoid carcinoma of salivary glands. This evidence concerns the gene NANOG and hidradenoma.