© 2002 Nature Publishing Group

It is widely accepted that many of the molecular pathways that underlie carcinogenesis represent aberrations of the normal processes that control embryogenesis. There are many examples in which the anomalous expression of genes that regulate growth and development have been implicated in carcinogen-esis. Among the principal examples are HOMEOBOX genes, which encode transcriptional regulatory pro-teins (HOMEOPROTEINS) that are widely used during development and are often aberrantly expressed in cancer (BOX 1). Based on their global significance for development and differentiation, and their frequent deregulation in cancer, homeobox genes provide an ideal focal point to explore the intimate relationship between oncogenesis and embryogenesis