There is controversy in the medical community about whether triple-positive breast cancer is a distinctive subtype of the disease.
It will also discuss treatment options and how this pop in of cancer is diagnosed.
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Illustration by Mira Norian for Verywell Health
What Does ‘Receptor Positive’ Mean?
Normal breast cells have estrogen and human epidermal growth factor receptor 2 (HER2) receptors.
In receptor-positive tumors, there are a lot more of these receptors.
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When the hormone estrogen binds to estrogen receptors, it stimulates cell growth.
The same thing happens with another hormone, progesterone.
With HER2, the growth factors bind to the receptor to stimulate growth.
Overall, roughly 10% of breast cancer tumors might be considered triple-positive.
However, large-scale studies looking at how common these tumors are and who gets them are lacking.
Its also important to know that the extent of estrogen positivity can vary between the tumors.
Breast cancers that are exclusively PR-positive are extremely rare.
Triple-Positive vs. HER2-Positive
Breast cancers that are HER2-positive can vary a lot.
Triple-positive breast cancers are also more likely to have positive lymph nodes than cancers that are only ER-positive.
This may influence the symptoms of triple-positive breast cancer.
However, that does not appear to be the case.
While some triple-positive tumors act more like ER-positive tumors, some tumors have similarities to triple-negative tumors.
Cancers that are triple-positive may act differently than would be expected based on HER2 or ER positivity alone.
The cancers can be affected by the relationship between the receptors, an interaction thats called “crosstalk.”
The interaction between HER2 and ER receptors is called “crosstalk.”
This crosstalk might explain why responses to hormonal therapy or HER2-targeted therapy are not always what would be expected.
The crosstalk between HER2 and ER may signal hormonal resistance.
In other words, communication between the receptors may make anti-estrogen therapy less effective in triple-positive tumors.
In addition, somebreast cancer chemotherapyregimens work better or worse for HER2-positive tumors.
Metastatic triple-positive breast cancer is usually treated differently frommetastatic HER2-positive breast cancer.
This regimen can be followed by hormonal therapy (such as anaromatase inhibitor).
If these tests show something that looks suspicious, abiopsyis done.
Samples of the tumor tissue removed during a biopsy are looked at under a microscope.
The results are given a rating of 0 to 3.
A score of 0 means that a tumor is HER-negative or HR-negative.
A score of 3 confirms that a tumor is positive for HER2 or HR-positive.
Scores of 1 and 2 are considered borderline.
There was no statistically significant difference in five-year survival between the two subtypes in stage 3.
Hormone status and HER2 status of tumors are diagnosed using an immunohistochemistry test.
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