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Official Description

Oncoprotein; HER-2/neu

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The HER-2/neu oncoprotein is a significant cell surface growth factor receptor that plays a crucial role in the regulation of normal cell division and growth. This protein is primarily expressed on the membranes of certain epithelial cells, where it functions to facilitate communication between cells and promote healthy cellular activities. However, when there is an abnormal increase in the number of HER-2/neu proto-oncogenes within the cell nucleus, it leads to the overproduction of this oncoprotein. This overexpression can result in accelerated cell growth rates and mutations, ultimately contributing to the transformation of normal cells into cancerous cells. To assess the presence and quantity of HER-2/neu oncoprotein, immunohistochemistry methods are employed. These methods utilize specific antibodies that bind to the HER-2/neu protein, followed by a staining process that allows for the visualization and quantification of the oncoprotein on the cell membrane. This evaluation is critical for understanding the potential for malignancy and guiding treatment decisions in oncology.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The HER-2/neu oncoprotein testing is indicated for the following conditions:

  • Breast Cancer Testing for HER-2/neu is primarily indicated in patients diagnosed with breast cancer to determine the overexpression of the oncoprotein, which can influence treatment options and prognostic outcomes.
  • Gastric Cancer The assessment of HER-2/neu is also indicated in patients with gastric or gastroesophageal junction cancers, as overexpression may affect therapeutic strategies.

2. Procedure

The procedure for testing the HER-2/neu oncoprotein involves several key steps that ensure accurate detection and quantification of the protein.

  • Sample Collection A tissue sample is obtained from the patient, typically through a biopsy of the tumor. This sample is crucial for the subsequent analysis of HER-2/neu expression.
  • Preparation of Tissue Sections The collected tissue sample is then processed and prepared into thin sections that can be placed on slides for examination. This preparation is essential for the application of immunohistochemistry techniques.
  • Application of Antibodies Specific antibodies that target the HER-2/neu oncoprotein are applied to the prepared tissue sections. These antibodies bind to the HER-2/neu protein present on the cell membranes of the epithelial cells.
  • Staining Process Following the antibody application, a staining process is conducted to visualize the bound antibodies. This typically involves the use of secondary antibodies that are conjugated to a detectable marker, allowing for the identification of the HER-2/neu oncoprotein.
  • Microscopic Evaluation The stained tissue sections are then examined under a microscope by a pathologist. The pathologist assesses the intensity and distribution of the staining to determine the level of HER-2/neu expression, which is critical for making informed clinical decisions.

3. Post-Procedure

After the HER-2/neu testing procedure, the tissue samples are typically preserved for further analysis if needed. The results of the immunohistochemistry test are usually reported within a few days, providing essential information regarding the HER-2/neu status of the tumor. This information is vital for oncologists to tailor treatment plans, including the potential use of targeted therapies such as trastuzumab (Herceptin) for patients with HER-2/neu positive breast or gastric cancers. Patients may be monitored for any side effects related to the biopsy procedure, and follow-up appointments are scheduled to discuss the results and subsequent treatment options.

Short Descr ONCOPROTEIN HER-2/NEU
Medium Descr ONCOPROTEIN HER-2/NEU
Long Descr Oncoprotein; HER-2/neu
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 233 - Laboratory - Chemistry and Hematology
90 Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number.
Date
Action
Notes
2011-01-01 Changed Short description changed.
2009-01-01 Changed Code description changed
2002-01-01 Added First appearance in code book in 2002.
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Description
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Description
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