Breast cancer is the most common malignancy in women. Approximately 18–20 percent of breast cancers show amplification in the human epidermal growth factor receptor-2 gene (HER2). Amplification of this gene results in the increased membrane expression of the HER2 protein. This increased amount leads to increased dimerization, which activates the HER2 tyrosine kinase. This activation signal is transmitted to the cell nucleus. The cell responds by mitosis and cell replication. Her-2/neu is an oncogene. It is a gene that codes for a protein that is a receptor for a particular growth factor that promotes cell growth. Normal epithelial cells found throughout the body contain two copies of the Her-2/neu gene and produce low levels of the Her-2/neu protein on the surface of their cells. In about 20-30% of invasive breast cancers (and some other cancers, such as ovarian and bladder cancer), the Her-2/neu gene is amplified and its protein is over-expressed. Tumors that have this over-expression tend to grow more aggressively and resist endocrine (anti-hormone) therapy and some chemotherapies. People with Her-2/neu positive breast cancers tend to have a poorer prognosis, but this tumor characteristic also makes them candidates to receive treatment specific for Her-2/neu-positive cancers.
This test is not used for screening purposes and is not a substitute for tissue testing but may be ordered to help assess a person's prognosis and to monitor the effectiveness of treatment. After an initial diagnosis of metastatic breast cancer is made, this blood test may be performed and, if the initial level is greater than 15 ng/mL, then the test may be used to monitor treatment. After a diagnosis of metastatic breast cancer has been made, Her-2/neu testing may be used as a prognostic marker to help determine how aggressive the breast cancer tumor is likely to be. It is usually ordered along with estrogen and progesterone hormone receptor status tests (ER and PR). The results of these three tests give the doctor information about the person's likely prognosis and response to specific therapies such as hormone therapy and chemotherapy. The serum Her2/neu test is sometimes used to monitor Her2/neu-positive breast cancer patients who are receiving cancer therapy including, for example, hormone therapy, chemotherapy, or Her-2/neu targeted therapy. If the level of serum Her-2/neu is initially elevated (greater than 15 ng/mL) then falls, it is likely that treatment is working; if it stays elevated, treatment is not working; and if the level falls then rises, the cancer may be recurring.
Taqman Real time PCR assay
• Diagnosed with invasive breast cancer.
• Determine whether the Her-2/neu gene is being over-expressed in the tumor.
• Initial diagnosis to establish a baseline value and then used periodically to monitor the person's response to treatment.
• Nonspecific symptoms such as fatigue, weight loss, joint or bone pain, and/or an enlarged spleen or as a follow-up to abnormal findings on
a CBC.
• All pregnant women.
• HIV-positive persons.
Every day.
3-4 days.
Breast cancer tissue Biopsy .Blood, Collect in: Lavender (EDTA), pink (K2EDTA). Stability collection to initiation of testing On Cells: Ambient: 4 hours; Refrigerated: 48 hours; Frozen at -20°C: 72 hours; Frozen at -70°C: 4 months. Do not thaw avoid repeated freezing and thawing.
NOTE: Sample of breast cancer tissue obtained during a biopsy or a tumor removed surgically during a lumpectomy or mastectomy; sometimes a blood sample drawn from a vein in your arm. Sample of breast cancer tissue is obtained by doing a fine needle aspiration, needle biopsy, or surgical biopsy.
Refrigerate specimen's at 2°C-4°C.
Heparinized specimens, Hemolysis sample, Quantity not sufficient for analysis, specimen grossly contaminated, specimen too old, frozen whole blood specimen, specimen leaky or tube broken.
Assay uses sequence-specific hybridization probes to detect a target (HER2/neu) and a reference gene (β-globin) simultaneously. Its ease of use and broad dynamic range allows screening for amplification of HER2-neu. Real Time Polymerase chain reaction (PCR)-based assays are able to determine both changes in HER-2-neu gene number and expression. It is The over expression of Her-2-neu gene which is significant related to Active Breast cancers, prostate cancers & not the detection or prevalence alone of Her-2-neu.The ratio of Her-2-neu & β-Globin should always be used as the markers for comparison of the patient data This test can detect and Differentiate HER-2-neu/β-globin Gene gene over the range 110-109copies/mL. The ratios obtained can be interpreted as follows.
Her-2-neu/β-Globin ratio of ≤ 2.2 can be interpreted as negative for over expression/amplification of Her-2-neu.
Her-2-neu/β-Globin ratio of 2.2-2.5 can be interpreted as equivocal for over expression/amplification of Her-2-neu.
Her-2-neu/β-Globin ratio of ≥ 2.5 can be interpreted as positive for over expression/amplification of Her-2-neu.
The result of this test must always be correlated with clinical status and history of the patient and other relevant data and should not be used alone for the interpretation.