Thyroid hormone receptors in breast cancer: prognosis, predictive and therapeutic implications.

Researchers: Dr. B Dhesy

Dhesy

Bindi Dhesy

The survival of breast cancer patients has improved in the past 20 years due to advancements in anti-hormonal and anti-HER2 directed therapies. These therapies benefit patients whose cancers display hormone receptors called estrogen receptor (ER) and/or progesterone receptor (PR), or a cancer promoting protein called HER2. However 20% of breast cancer patients are ER, PR, and HER2 negative with so-called “triple negative” disease. Due to a lack of targeted therapies, these patients have high rates of cancer recurrence and poor survival. It is possible that other hormone receptors (e.g. thyroid hormone absence of ER/PR and HER2. If so, these receptors may help doctors find new treatments and better predict how aggressively a tumour will behave.

Our preliminary work on thyroid hormone receptors (THRs) in 130 breast cancer patients showed that women whose tumours were positive for a specific THRs (THRa2), lived 22% longer than those who were negative. We will validate these findings in a much larger sample of 1601 patients, whose tumours are archived in the Henrietta Banting Breast Centre database at Women’s College Hospital (Toronto, ON). If this analysis yields promising results, THRa2 will be assessed in a clinical trial population to see if it predicts patients’ response to anti-hormonal therapy. Finally, we will explore the possibility that THRa2 may be a target for novel treatments through laboratory experiments.