The ability of FETα cells to carry out invasion at the primary site, but not carry out subsequent aspects of the metastatic cascade due to TGFβ signaling suggests that this tumor suppressor activity is strong enough to shift the balance of tumor suppressor/oncogenesis signaling toward cell death when these cells encounter the stresses associated with various steps that must be traversed in the metastatic process such as circulation in the blood and/or colonization in the foreign microenvironment of distant organs (reviewed by Mehlen and Puisieux [4]). This evidence concerns the gene TGFB1 and neoplasm.