Endometriosis: candidate genes.

Endometriosis is generally regarded as a benign disease but it does exhibit some characteristics reminiscent of malignancy. This raises the possibility that, like malignant diseases, the development of endometriosis may involve the acquisition of somatic genetic alterations in genes that regulate cell growth and differentiation. Studies over the past few years have substantiated this view with the identification of a variety of genetic abnormalities usually only associated with malignancies. Our own studies have shown that genetic alterations, as shown by loss of heterozygosity, are relatively common in endometriosis implying that tumour suppressor gene inactivation is likely to be involved in the proliferation and maintenance of all endometriotic implants. We have also shown by DNA fingerprinting that endometriotic lesions found adjacent to ovarian cancers have a common lineage, reinforcing the compelling histological and epidemiological data that endometriosis is a precursor of endometrioid and clear cell ovarian cancers. It is now well accepted that susceptibility to endometriosis may also involve an inherited genetic component. Studies aimed at identifying the predisposing genes are still in their infancy but should eventually provide invaluable insights into the pathology and aetiology of endometriosis.