HER2 (human epidermal growth factor receptor 2) - Cancer Science

What is HER2?

HER2, or human epidermal growth factor receptor 2, is a protein that plays a crucial role in the growth and proliferation of cells. It is a member of the EGFR (epidermal growth factor receptor) family, which includes four structurally related receptors. HER2 is encoded by the ERBB2 gene located on chromosome 17. When the HER2 gene is amplified, it leads to overexpression of the HER2 protein, which can result in uncontrolled cell growth and cancer.

How is HER2 related to Cancer?

HER2 overexpression is found in a significant percentage of certain types of cancer, most notably breast cancer and gastric cancer. In these cancers, HER2-positive status is associated with a more aggressive disease course and a poorer prognosis. HER2-positive breast cancer accounts for approximately 20-25% of all breast cancer cases.

Why is HER2 Testing Important?

Testing for HER2 status is crucial for determining the appropriate treatment strategy. Several methods are used for HER2 testing, including immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Accurate HER2 testing ensures that patients who are HER2-positive receive targeted therapies that can significantly improve their outcomes.

What are the Treatment Options for HER2-Positive Cancers?

The treatment landscape for HER2-positive cancers has evolved significantly with the development of targeted therapies. Some of the most commonly used HER2-targeted therapies include:

Trastuzumab (Herceptin): A monoclonal antibody that binds to the HER2 protein, inhibiting its activity.
Pertuzumab (Perjeta): Another monoclonal antibody that prevents HER2 from dimerizing with other HER receptors, thereby blocking signaling pathways that promote tumor growth.
Ado-trastuzumab emtansine (T-DM1, Kadcyla): An antibody-drug conjugate that combines trastuzumab with a chemotherapy agent to deliver targeted treatment to HER2-positive cells.
Lapatinib (Tykerb): A small molecule tyrosine kinase inhibitor that blocks the intracellular signaling pathways of HER2.

What are the Side Effects of HER2-Targeted Therapies?

While HER2-targeted therapies are generally well-tolerated, they can have side effects. Common side effects include fatigue, nausea, diarrhea, and a risk of cardiac toxicity. It is essential for patients to be closely monitored by their healthcare providers to manage these side effects effectively.

What is the Prognosis for HER2-Positive Cancer Patients?

The prognosis for HER2-positive cancer patients has improved dramatically with the advent of targeted therapies. Prior to the availability of these treatments, HER2-positive cancers were associated with a poor prognosis. However, with therapies like trastuzumab and pertuzumab, patients now have significantly better survival rates and quality of life.

Are There Any Emerging Therapies for HER2-Positive Cancers?

Research is ongoing to develop new and more effective therapies for HER2-positive cancers. Some of the promising areas of investigation include bispecific antibodies, immune checkpoint inhibitors, and CAR-T cell therapy. These emerging treatments aim to enhance the precision and efficacy of cancer treatment while minimizing side effects.

How Can Patients Access HER2-Targeted Therapies?

HER2-targeted therapies are widely available and are part of standard treatment protocols for HER2-positive cancers. Patients should discuss their HER2 status with their oncologists to determine the best course of action. Additionally, clinical trials may offer access to new and experimental therapies for eligible patients.