Various approaches, using different biological systems [5,6,7] led to the identification of at least 300 genes that could be implicated in the tumor reversion process, including siah1, PS1, TSAP6, TCTP, Integrin receptors, and Nodal. Interestingly, Nodal is an embryonic morphogen recently found to be a key plasticity gene in aggressive tumor cells. This evidence concerns the gene SIAH1 and neoplasm.