In the case of melanoma, these dependencies are shown to be defined by the very early body axis and limb patterning developmental programs defined by HOXB/HOX13 while in the case of colon cancers the differences in the proximal and distal colon epithelial cells arise due to differential gene expression control by later organ developmental programs regulated by the parahox CDX2. The gene discussed is HOXA5; the disease is melanoma.