The follicle stimulating hormone, FSH, targets the human reproductive organs: the ovaries and testicles. In women, it stimulates maturation of ovarian follicles and production of oestrogens (via its action on granulosa cells). In men, it stimulates production of spermatozoa (via its action on the Sertoli cells).

FSH receptor, which was the subject of the work carried out by the Inserm researchers, is normally only found in cells stimulated by FSH (granulosa cells in women and Sertoli cells in men). However, it is also present in very small quantities in the blood vessels of the ovaries and testicles...and this is what alerted the researchers.

The vascular network is one of the most important constituents of cancerous tumours. It is essential to their maintenance and growth in the organism. The majority of cancerous tumours can even create new vessels in order to survive. The researchers, therefore, undertook an in-depth study aimed at determining if FSH receptor was present in the blood vessels of tumours.

1336 patients and 11 cancers

Nicolae Ghinea and his colleagues from Inserm studied biopsies taken, after surgery, from 1336 patients afflicted with cancer. The presence of FSH receptor was monitored in the tumours, which ranged from being at a very early stage to being at the later stages, for 11 types of cancer (cancers of the prostate, breast, colon, pancreas, bladder, kidneys, lungs, liver, stomach, testicles and ovaries).

The results obtained demonstrated the presence of this receptor in all the samples, regardless of the type or stage of the tumour. By contrast, this receptor was totally absent in the other normal tissues of the organism, including the normal tissue of the organ that was carrying the tumour.

Simple detection by imaging

In general, blood vessels which express FSH receptor are found at the periphery of the tumour. The receptor is specifically localized on the surface exposed to the blood (luminal) of the endothelial cells, which carpet the vessel walls (see box), making them an easy target for diagnostic and therapeutic agents injected in the blood.

These two characteristics (absence from normal tissues and localization on the luminal surface of endothelial cells) make it a very promising biological marker and an interesting candidate for imaging and therapy. The researchers have already performed successful detection experiments through imaging in mice.

Towards clinical confirmation

Further experiments are required to confirm the detection of the FSH receptor by testing imaging procedures currently used in hospitals (MRI, PET and ultrasound imaging). The researchers believe that this receptor will be able to act as a general target for anti-cancer drugs as well as for agents which destroy or block blood vessels in tumours.