Circulating tumour cells (CTCs) have significant diagnostic potential as they can
reflect both the presence and recurrence of a wide range of cancers. However, this potential
continues to be limited by the lack of robust and accessible isolation technologies. An
alternative to isolation might be their direct detection amongst other peripheral blood cells,
although this would require markers that allow them to be distinguished from an exceptionally
high background signal. This review assesses the potential role of HOX genes, a family of
homeodomain containing transcription factors with key roles in both embryonic development
and oncogenesis, as unique and possibly disease specific markers of CTCs.