The PTEN (Phosphatase and Tensin Homolog) gene is one of the main tumour suppressors in our bodies. When working correctly, it helps to control the life cycle of cells; when it is not fully functioning, on the other hand, cells can grow in an uncontrolled way, creating tumours.

Diseases caused by malfunctioning of this gene are very rare (affecting one person in every 200 000). The blanket term for them is PHTS (PTEN Hamartoma Tumour Syndrome), and they include: Bannan Riley Ruvalcaba syndrome, Cowden syndrome, Proteus-Like syndrome and Lhermitte-Duclos disease.

The main clinical concern for people suffering from PHTS is the high risk of breast cancer and cancers of the endometrium, thyroid, kidney and colon, as well as melanoma.

There are no specialised treatment centres in Europe for patients affected by these diseases, and the main way of dealing with them is by seeking to diagnose cancer at a very early stage.