Is Estrogen receptor/Progesterone receptor status of Breast Cancer related to Race?

Oestrogen receptors are protein molecules found inside the cell for which estrogen has an affinity. Estrogen is a hormone helping in the development of secondary sexual characteristics in females. All the cells in the body do not have estrogen receptors. The tissues with cells having estrogen receptors are called target tissues for the action of estrogen. When estrogen combines with estrogen receptors in target tissues, it may help in the growth and multiplication of cells in that tissue. Otherwise, it can be stated that cells with estrogen receptors require estrogen for its growth and multiplication. Progestrone receptor is also a protein molecule found in some cells of the body, where the hormone progesterone can get attached and may cause the cell to grow.

Patients having estrogen receptors on the breast cancer cells are said to have estrogen receptor positive status. It is advantageous to have estrogen receptors and progestron receptors on the breast cancer cells if you have breast cancer, because then it can be treated with hormone therapy. So we can say patients who are estrogen receptor positive have a sluggish course to their disease and have better prognosis. Such tumors grow with the help of hormones. So if the hormone supply to these tumor cells is prevented, their growth can be controlled and recurrence avoided.

Estrogen receptor positive and progesterone receptor positive tumors are treated with anti estrogen therapy. The aim of treatment is to lower the level of estrogen in the body and to prevent estrogen from attaching to the estrogen receptors thereby preventing cell signalling and growth. Anti estrogen therapy has proved to be good in preventing recurrence of breast cancer and the most common drug used is Tamoxifen. Other drugs include raloxifene, anastrozole, exemestane, letrozole and fulvestrant. Tamoxifen belongs to the category of Selective Estrogen Receptor modulator (SERM) and is given orally.

So we have seen that it is advantageous to have hormone receptor positive breast tumors, because of the treatment options available. But, there are some recent studies stating that the hormone receptor status varies according to the race of the patient.

A study conducted by Dr. Ward and colleaugues found that there are more number of black women compared with white women having estrogen- or progesterone-receptor (ER/PR) negative breast cancer. They also found that black women had a 2.26 times chance of getting diagnosed with ER/PR-negative than with ER/PR-positive breast cancer compared to white women.

Another study conducted by Department of Pathology, Tata Memorial Hospital, Mumbai, India showed that, out of the 798 breast tumors studied, 46.5% were Estrogen receptor negative and progesterone receptor negative.

There is yet another study published in BMCCancer 2010,assessed the United States National Cancer Institute's Surveillance Epidemiology and End Results (SEER) Cancer program and found that Indian and Pakistani women in U. S have higher frequency of ER/PR negative breast cancer

Many more such studies are required under different settings to reach at a conclusion and to explore the reasons for these racial variations in hormone receptor status.