The complete answer to your question is very complex. Isn't it always? I'll do my best to stick to what I believe is the essence of your question. For the purpose of this discussion, I will be referring to the Estrogen Receptor (ER) as it applies to both normal and cancerous breast tissue in the setting of chemotherapy. If I miss the point, elaborate and I'll attempt to provide a better answer for you.
Strictly speaking, the breast tissue Estrogen Receptor is both genetic AND variable in the presence of chemotherapy (and other medications).
I like to think of the Estrogen Receptors as the part of the breast tissue that provides the normal "stickiness" for the circulating estrogen in the body. The more Estrogen Receptors there are, the more the circulating estrogen in the blood stream will stick around and interact with the the breast cells. If the breast tissue is extremely "sticky" to estrogen, it is considered highly Estrogen Receptor positive (ER+). At any given time in life, the amount of normal "stickiness" that breast tissue has for estrogent will vary slightly. This is due to many different factors including the normal hormonal cycle, genetic background AND medication (among others).
When estrogen sticks around the normal breast tissue, it influences the breast tissue to behave in a certain ways. One of the normal effects of estrogen on the breast tissue is the stimulation of growth (note, this is sometimes noticed in patients as breast tenderness and fullness).
When breast tissue becomes cancerous, the genetic make-up of the cells changes and the cancerous cells begin to "break some of the rules of normal behavior." Evaluating these cells for the presence of Estrogen Receptors is useful to know in order to have an idea of how the cancerous cells are behaving. If the cancer is Estrogen Receptor positive (ER+), we can limit the amount of estrogen in the blood stream to try to prevent the cancer from growing. If the cancer is Estrogen Receptor negative, we can focus on other strategies. Note, with time, cancer can break additional rules and the receptor status can change.
I hope this helps answer your question!
Ryan Polselli, M.D., Breast Imaging Radiologist
This answer is for general informational purposes only and is not a substitute for professional medical advice. Always seek the advice of your doctor before starting or changing treatment.
Strictly speaking, the breast tissue Estrogen Receptor is both genetic AND variable in the presence of chemotherapy (and other medications).
I like to think of the Estrogen Receptors as the part of the breast tissue that provides the normal "stickiness" for the circulating estrogen in the body. The more Estrogen Receptors there are, the more the circulating estrogen in the blood stream will stick around and interact with the the breast cells. If the breast tissue is extremely "sticky" to estrogen, it is considered highly Estrogen Receptor positive (ER+). At any given time in life, the amount of normal "stickiness" that breast tissue has for estrogent will vary slightly. This is due to many different factors including the normal hormonal cycle, genetic background AND medication (among others).
When estrogen sticks around the normal breast tissue, it influences the breast tissue to behave in a certain ways. One of the normal effects of estrogen on the breast tissue is the stimulation of growth (note, this is sometimes noticed in patients as breast tenderness and fullness).
When breast tissue becomes cancerous, the genetic make-up of the cells changes and the cancerous cells begin to "break some of the rules of normal behavior." Evaluating these cells for the presence of Estrogen Receptors is useful to know in order to have an idea of how the cancerous cells are behaving. If the cancer is Estrogen Receptor positive (ER+), we can limit the amount of estrogen in the blood stream to try to prevent the cancer from growing. If the cancer is Estrogen Receptor negative, we can focus on other strategies. Note, with time, cancer can break additional rules and the receptor status can change.
I hope this helps answer your question!
Ryan Polselli, M.D., Breast Imaging Radiologist
This answer is for general informational purposes only and is not a substitute for professional medical advice. Always seek the advice of your doctor before starting or changing treatment.