Characterization of Receptors in Non-functioning Pituitary Macroadenomas

Characterization of receptors present in non-functioning pituitary macroadenomas by Reverse Transcriptase- Polymerase Chain Reaction (RT-PCR) would assist with targeted medical therapy based on the information obtained by immunohistochemistry and RT-PCR.

The pituitary gland in the brain is the master hormonal gland and is surrounded by important nerves and blood vessels. The pituitary gland can develop various types of tumors, some which do not produce any hormones and are called non-functioning pituitary adenomas. These non-functioning tumors can grow and can cause compression of these important structures. The usual treatment of large non-functioning pituitary macroadenoma is surgery. As it is surrounded by neuro-vascular bundles, this makes complete removal of the tumor sometimes impossible and even dangerous. A large number of subjects will still have some residual tumor post-surgery. The risks of residual tumor are further growth with compression and compromise of the function of surrounding vital organs especially vision.

If there is further growth of the tumor the options at present are repeat surgery or radiotherapy. Repeat surgery involves all the risks associated with brain surgery and sometimes may not be possible if very close to vital organs, while radiotherapy will over a period of time lead to complete or partial deficiency of pituitary hormone function and has been associated with long term cognitive deficits. In addition radiotherapy has a lag time of 12-24 months prior to onset of action.

However, pituitary tumors that do not actively secrete hormones may still harbour receptors to various hormones. The blockage of these receptors by various medications may enable us to stop the tumor from growing or recurring after surgery. This may open up a novel means of treatment of these non functioning tumors. So far there is very little information in the literature about the type of receptors present in these tumors.

Our study proposes to obtain a piece of the tissue removed during surgery and perform receptor characterization to help improve our knowledge in that area. Also correlating the receptor status with the clinical, hormonal and radiological profile of the patients may help to develop improved treatment strategies in the future and help us to predict the possibility of tumor regrowth.

All subjects who are diagnosed with a non-functioning pituitary macroadenoma who are scheduled for surgery.

Inclusion Criteria:

1. Adults, both males and females age 18 years old or more
2. Pituitary tumor more than 10 mm in diameter diagnosed by MRI
3. No clinical or laboratory evidence of pituitary hormone oversecretion (non-functioning pituitary macroadenoma)

Exclusion Criteria:

1. Subjects with pituitary tumors less than 10 mm in diameter
2. Subjects with clinical or laboratory evidence of hormone oversecretion
3. Presence of dementia