Heterotopic expression of homeobox genes as a cause of organ specific metastasis

Organ- and tissue-specific metastases have been proposed as an alteration of invasion, translocation through vascular channels, lodgment, and local proliferation. However, experimental metastasis without tumor formation at the primary site can not be explained by these hypotheses. We hypothesize here that tumor cells heterotopically express homeobox genes as a marker of their location, and that they translocate elsewhere according to positional information encoded in these genes.