The role of Engrailed developmental genes in gynaecological cancer.

Homeobox genes encode a superfamily of transcriptional regulators involved in the growth and development of human tissues and organs. Engrailed (En) genes are homeodomain genes, which have transcription factor functions and play a significant role in vertebrate embryonic development. The EN proteins comprise two members, Engrailed-1 (EN1) and Engrailed-2 (EN2). These proteins have been implicated in cancer development in various adult tissues, acting either as oncogenes or tumour suppressors depending on the context and cell type. Their expression has also been investigated in urinary cancers such as prostate and bladder cancer, where they have been proposed as non-invasive biomarkers detectable in urine. Studies in gynaecological tissues have suggested EN1 and EN2 may act as oncogenes in breast and ovarian cancer; however, research into their roles in other gynaecological cancers, such as endometrial, cervical and vaginal cancer, remains preliminary.