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HER-2/neu oncomarker in blood
Medical expert of the article
Last reviewed: 05.07.2025
Reference values (norm) for HER-2/neu concentration in blood serum are less than 15 ng/ml.
Oncomarker HER-2/neu - human epidermal growth factor receptor - a protein found on normal cells of epidermal origin with a molecular weight of 185,000. It consists of 3 functional parts: internal (cytosolic), short transmembrane and extracellular. The cytoplasmic region of the HER-2/neu receptor molecule has tyrosine kinase activity and is responsible for signal transmission. The hydrophobic transmembrane part connects the intracellular kinase and extracellular ends of the receptor. As a result of proteolytic processes, the extracellular part of the HER-2/neu receptor enters the blood, where it can be identified. It is a glycoprotein with a molecular weight of 97,000-115,000.
Until recently, the presence of HER-2/neu receptors in breast cancer patients was determined histochemically after tumor puncture. These receptors are found in only 20-30% of women with breast cancer. The main purpose of histochemical testing is to determine the indications for treatment with trastuzumab (antibodies to HER-2/neu receptors), which is indicated when more than 10% of positive cells (2+ or 3+) are detected. It was later found that a significant proportion of breast cancer patients respond positively to trastuzumab treatment with a negative histochemical test result.
Currently, test systems have been developed for the quantitative determination of HER-2/neu in blood serum, which correlates well with the data of histochemical examination. An increase in the concentration of HER-2/neu in the blood serum is observed in women with breast cancer, especially in the presence of metastases. The value of 15 ng/ml is used as a cutoff point. Values above this level indicate HER-2/neu-positive breast cancer. An increased level of HER-2/neu strongly correlates with a poor prognosis, low survival and an aggressive course of the disease (such tumors have high proliferative and metastatic activity). Effective specific (trastuzumab), hormonal and chemotherapy are accompanied by a decrease in the level of HER-2/neu in the blood serum.
Determination of HER-2/neu content in blood serum is used:
- for monitoring metastatic breast cancer;
- to select patients for specific therapy (trastuzumab);
- for the diagnosis of recurrent breast cancer;
- to determine the prognosis and course of breast cancer;
- for monitoring specific therapy, as well as treatment with hormonal and chemotherapeutic drugs.
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