AR+
Meaning of AR+: A laboratory label from a tissue sample, marking cells that carry the docking site androgens use to send growth signals.
Definition of AR+
AR+ means androgen receptor positive: the cells tested carry androgen receptors, proteins that bind androgens such as testosterone and pass their signal into the cell. The label is used most often for cancer cells, where the receptor may allow androgen signaling to drive growth. It is established by laboratory testing of a tissue sample.
What does the receptor actually do?
An androgen circulating in the blood cannot act on a cell that has nothing to receive it. The androgen receptor is that receiver. When a hormone binds, the receptor changes shape, moves into the cell nucleus and attaches to DNA, switching particular genes on or off. In a tumor whose cells depend on that pathway, the switched-on genes are ones that push the cell to grow and divide. This is why receptor status is recorded rather than treated as a technical detail: it describes a route by which the cancer may be fed.
How is AR+ status established?
A pathologist stains a slice of the tumor with an antibody that sticks to the androgen receptor, then counts how many cell nuclei take up the stain and how strongly. The result is reported against a defined threshold, so a tumor sits above or below a cutoff rather than simply having or lacking the receptor. Thresholds and scoring methods are not identical between laboratories, which is one reason a result is read alongside the rest of the report.
How does it relate to other receptor markers?
| Marker | What binds it |
|---|---|
| AR | Androgens, including testosterone |
| ER | Estrogen |
| PR | Progesterone |
| HER2 | A growth factor signal, through a receptor on the cell surface |
The estrogen receptor and the androgen receptor belong to the same family of hormone receptors that work inside the cell, while HER2 sits on the cell surface and works differently. A tumor can carry more than one of these markers, and the combination reported is what describes its biology, not any single line.
Why does the status matter for treatment?
Where cells rely on androgen signaling, approaches that lower androgen levels or block the receptor itself can slow their growth. That principle is central in prostate cancer and is studied in other tumor types that express the receptor. Presence of the receptor is not the same as dependence on it, so the marker informs the picture rather than settling it.
Also known as
Used in a sentence
Pathology confirmed the tumor was AR+, a finding noted alongside other biomarker results in the report.
Good to know
AR+ records that androgen receptors were detected on the cells tested, which is not the same as the cells depending on androgen signaling, so receptor presence alone does not predict how a tumor will behave or respond.