Serum HER-2 levels increase in 18% of primary breast cancers and 46% of metastatic breast cancers. Therefore, it can be detected in the serum. The extracellular domain (ECD) can be released into the blood after cleavage and shedding from the tumor cell surface by metalloproteases. The HER-2 protein contains three different domains, including transmembrane, extracellular, and intracellular tyrosine kinase domain. In this way, score 2+ is uncertain and should be confirmed through FISH as a gold standard.
In this regard, IHC scored 3+ would be considered as positive status and 0/1+ as a negative status. It is highly recommended to use IHC for the evaluation of HER2 status. serum antigen measuring by Enzyme-Linked Immunosorbent Assay (ELISA) or chemiluminescence immunoassays (CLIA). protein expression measuring by Western blot and Immunohistochemical (IHC) analysis and 4. messenger RNA measuring by PCR or Southern blot analysis 3. gene copy measuring by polymerase chain reaction (PCR), Southern blot analysis, Chromogenic In Situ Hybridization (CISH) and Fluorescence In Situ hybridization (FISH) 2. There are several methods to determine the presence of HER-2, which are 1. Recently, this protein has gained significant attention as a biomarker as well as a target of diagnosis, prognosis, and therapy in breast cancer patients. have understood the importance of HER-2 as a diagnostic factor for breast cancer in 1987. As an oncogene, the amplification of HER-2 or its protein overexpression has a significant role in the development of malignant types of breast cancer, which observes in 20–30% of breast cancer patients. The human epidermal growth factor receptor-2 (HER-2/ neu) or c-erbB-2/neu is one of the epidermal growth factor receptor (EGFR) family members. In this regard, there are different types of diagnostic approaches for the detection of breast cancer, such as magnetic resonance imaging (MRI) of the breast, mammography, molecular imaging, biopsy, and ultrasound tomography. Previous investigations showed that the early detection and diagnosis of this malignancy could lead to promising treatment and improve the chance of successful therapy. As a heterogeneous complex disease, this malignancy includes different subtypes with different clinical outcomes and treatment responses. The most common deadly cancer among women is breast cancer throughout the world this condition is more severe in developing countries.
Hence, it seems that the measurement of serum HER-2 levels can play a significant role as a verification test for initial negative screening test results, especially in low-income regions due to its cost-effectiveness and ease of implementation.
Our findings revealed that although serum HER-2 levels showed low se nsitivity for breast cancer diagnosis, its specificity, accuracy and AUC were reasonable.
Resultsįourteen studies entered into this investigation. Meta-analyses were carried out for sensitivity, specificity, accuracy, area under the ROC curve (AUC), positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR). We performed a systematic search via PubMed, Scopus, Cochrane-Library, and Web of Science databases for human diagnostic studies reporting the levels of serum HER-2 in breast cancer patients, which was confirmed using the histopathological examination. We aimed to undertake a systematic review and meta-analysis focusing on the diagnostic/screening value of serum HER-2 levels in comparison to routine methods. Measurement of serum human epidermal growth factor receptor-2 (HER-2/ neu) levels might play an essential role as a diagnostic/screening marker for the early selection of therapeutic approaches and predict prognosis in breast cancer patients.