Hormone Receptor Status — Tumour Hormone Sensitivity

Hormone receptor status refers to the laboratory assessment of intracellular proteins—specifically oestrogen receptors (ER) and progesterone receptors (PR)—expressed by tumour cells. Normal breast and reproductive tissues possess these receptors to respond to physiological endocrine signals. When malignant transformation occurs, tumours may retain or lose these receptors depending on their underlying genomic and molecular alterations.

Pathologists evaluate tissue biopsies to ascertain the percentage and intensity of tumour cell nuclei displaying receptor expression. Tumours with significant nuclear staining are deemed hormone receptor-positive, indicating that circulating hormones promote cellular proliferation. Conversely, receptor-negative tumours lack these targets, reflecting an alternative molecular pathogenesis that relies on different pathways to sustain growth and survival.

Knowing hormone receptor status directly alters the therapeutic strategy. Hormone receptor-positive tumours generally demonstrate a more favourable short-term prognosis and are susceptible to endocrine therapies that reduce recurrence risk. Conversely, hormone receptor-negative tumours do not benefit from anti-hormonal medications, sparing patients ineffective treatments and unnecessary side effects. This classification ensures that therapeutic plans are customised to the biological profile of each tumour, optimising clinical benefit.

Testing is routinely performed on formalin-fixed, paraffin-embedded tissue obtained via core biopsy or surgical resection. Pathologists utilise immunohistochemistry (IHC) to detect oestrogen and progesterone receptors within cell nuclei. Results are typically reported as the percentage of stained cells and staining intensity, often quantified using standard scoring systems like the Allred score or H-score.

Hormone receptor status is evaluated most routinely in breast cancer. It is also assessed in gynaecological malignancies, including endometrial carcinomas and certain ovarian tumours. In prostate cancer, the related androgen receptor is critical for determining hormone sensitivity, while neuroendocrine tumours may express distinct endocrine receptors, such as somatostatin receptors, reflecting their specialised neuroendocrine origins.

Patients with receptor-positive breast tumours generally receive endocrine therapies, such as selective oestrogen receptor modulators (e.g., tamoxifen), aromatase inhibitors (e.g., letrozole, anastrozole), or selective oestrogen receptor degraders (e.g., fulvestrant). These agents may be combined with targeted CDK4/6 inhibitors. Receptor-negative disease typically relies instead on chemotherapy, immunotherapy, or HER2-targeted agents, as endocrine therapies provide no therapeutic benefit.