HOXB7 and melanoma: It is well known that the interaction between HOX proteins and their PBX cofactors is dependent on a short stretch of highly conserved amino acids in the amino terminal of the HOX protein, identified as the hexapeptide sequence.10,11 Here we investigated whether a direct HOXB7/PBX2 interaction does exist and if this heterodimeric binding is functionally required for melanoma induction and/or progression.