Human Epidermal Growth Factor Receptor 2
Human epidermal growth factor receptor 2 (Her-2) is an important biomarker in oncology, recognized for its critical role in a variety of diseases.
What is Her-2?
Her-2, also known as ERBB2, is a transmembrane protein and a member of the epidermal growth factor receptor family. Its primary function is to regulate cell growth, differentiation and survival. The Her-2 gene is located on chromosome 17 and encodes this receptor. When expressed at normal levels, Her-2 contributes to regular cellular processes. However, aberrant overexpression of Her-2 may lead to pathological consequences.
Her-2 as a Biomarker
Her-2 overexpression is strongly associated with breast cancer, particularly in approximately 15-20% of cases. In this context, Her-2 serves as a predictive and prognostic biomarker. Not only does it identify a subset of breast cancer patients who are more likely to benefit from targeted therapies, it also identifies more aggressive form of the disease. Herceptin (trastuzumab), a monoclonal antibody that targets Her-2, has revolutionized the management of Her-2-positive breast cancer.
Her-2's biomarker role also extends to gastric cancer. Identifying Her-2 positivity in gastric cancer patients can help tailor treatment strategies. This biomarker helps select patients for targeted therapy, thereby improving outcomes.
In ovarian cancer, the importance of Her-2 as a biomarker correlates with prognosis. Her-2 positivity in ovarian cancer often indicates a more aggressive disease course, affecting treatment decisions and patient counseling.
In addition to breast, gastric, and ovarian cancer, Her-2 overexpression is observed in several other malignancies. The biomarker potential of Her-2 in diseases such as lung, endometrial, and bladder cancer is the subject of ongoing research.
Detection Methods for Her-2
Accurate detection of Her-2 status is crucial for informed clinical decision-making. Several methods are available, each with its advantages and applications.
- Immunohistochemistry (IHC)
IHC is a widely used method to assess Her-2 expression. It involves staining tissue samples with specific antibodies against Her-2. Assess the degree and intensity of staining under a microscope. Results are typically graded on a scale from 0 to 3+, where 3+ indicates strong Her-2 expression.
- Fluorescence In Situ Hybridization (FISH)
FISH is a molecular technique designed to detect amplification of the Her-2 gene. It is particularly valuable when IHC results are inconclusive (2+). FISH directly examines the number of copies of the Her-2 gene in cells, distinguishing gene amplification from protein overexpression.
- Chromogenic In Situ Hybridization (CISH)
CISH is similar to FISH and focuses on amplification of the Her-2 gene. It uses chromogenic detection, simplifying interpretation. This is another way to assess Her-2 status, especially when clear results are needed.
- Next-Generation Sequencing (NGS)
While NGS is not a primary Her-2 detection method, it is a comprehensive approach to analyzing a patient's genetic profile, including Her-2 status. It can be valuable when studying multiple genetic markers simultaneously.
- Real-Time Polymerase Chain Reaction (RT-PCR)
RT-PCR is a molecular biology technique used to measure Her-2 gene expression at the RNA level. It provides a quantitative assessment of Her-2 expression and is particularly useful when studying gene regulation.
Her-2 is a multifaceted biomarker that has changed the landscape of disease diagnosis and management, particularly in breast and gastric cancers. As our understanding of Her-2 deepens, the future is expected to enhance diagnostics and treatments, ultimately leading to better patient outcomes in the field of precision medicine.
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