Overview: Estrogen Receptor Panel
Introduction: The Estrogen Receptor Panel is a diagnostic tool designed to assess estrogen receptor (ER) status in breast cancer using FFPE tissue samples. In India, breast cancer is the leading cancer in women (~178,000 new cases/year), with ER-positive tumors comprising ~60-70 percent of cases, strongly predicting response to endocrine therapy (tamoxifen, aromatase inhibitors). Accurate ER assessment is critical for prognosis and treatment selection. High morbidity from under-testing in rural/low-SES patients, limited IHC labs, delayed hormone therapy leading to progression or unnecessary chemotherapy toxicity. Per oncology practices aligned with ICMR, Indian Society of Medical Oncology, and ASCO/CAP guidelines, the test employs immunoassay for ER staining intensity and percentage positive cells over 1-2 days with high reproducibility, valuable for guiding adjuvant endocrine therapy. This diagnostic falls under cancer biomarker screening and targets breast cancer patients post-biopsy, addressing accurate detection to personalize treatment and improve survival. With elevated morbidity due to under-testing, the test supports public health efforts by enabling precise biomarker-driven therapy and reducing overtreatment. Its FFPE-based approach ensures reliable immunohistochemical analysis in India's expanding cancer centers.
Other Names: ER Pnl.
FDA Status: FDA approved, CLIA certified for oncology/histopathology, compliant with 2025 standards.
Historical Milestone: ER IHC standardized by ASCO/CAP; in India, mandatory in breast cancer protocols.
Purpose: The test assesses 3 parameters including estrogen receptor to guide breast cancer biomarker evaluation, determine ER status, inform endocrine therapy.
Test Parameters: 1. Estrogen Receptor, 2. Staining Intensity, 3. Percentage Positive Cells.
Pretest Condition: No fasting required; patients should have confirmed breast cancer diagnosis with FFPE tissue.
Specimen: FFPE tissue block (0.5-2 cm³), transported within specified times to maintain sample viability.Sample Stability: Indefinite when properly stored (paraffin-embedded blocks stable long-term).
Medical History: Patients should provide details on cancer stage, grade, menopausal status, prior therapy.
Consent: Written informed consent is required, detailing the test's purpose, potential risks of incorrect ER status including suboptimal therapy, benefits of biomarker assessment, and minimal discomfort (tissue already collected).
Procedural Considerations: The test involves sample processing using immunoassay (IHC) by trained personnel to ensure sterile technique, avoid artifacts, and interpret staining per ASCO/CAP criteria within 1-2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.
Factors Affecting Result Accuracy: Poor fixation, low tumor content, or delays can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.
Clinical Significance: ER-positive status indicates endocrine therapy benefit, necessitating specialist input. ER-negative may require alternative therapy.
Specialist Consultation: Medical oncologists should be consulted for management.
Additional Supporting Tests: PR, HER2 IHC/FISH for confirmation.
Test Limitations: Requires adequate tumor tissue; comprehensive approach required.
References: Indian Journal of Medical Oncology 2024, Breast Cancer Studies India 2023.
