The present invention relates to novel peptides, which impair PBX-dependent regulation of gene transcription and thus have utility in the treatment or prevention of disorders in which aberrant cell division occurs. In particular, the invention provides a peptide comprising the amino acid sequence (I): Y1X1X2KWX3X4X5X6X7Y2 (I)whereinthe sequence X1 to X7 is an amino acid sequence comprising at least 7 amino acids, which may optionally be interrupted by one or two amino acid residues between one or more of the 9 amino acid positions defined herein；X1 is selected from W, T, PE, KQI, VV, PQT, H, RI and absent；X2 is an amino acid with an aromatic side chain or cysteine；X3 is a hydrophobic amino acidX4 is an amino acid with a charged side chain；X5 is an amino acid with a basic side chain；X6 is an amino acid or absent；X7 is one or more amino acids or absent； andY1 and Y2 are each either absent or a peptide comprising a cationic polymer of basic amino acids, provided that at least one of Y1 and Y2 is present.
