What is HER2?
HER2, or Human Epidermal growth factor Receptor 2, is a protein that plays a crucial role in the regulation of cell growth and differentiation. It is found on the surface of some normal cells and is overexpressed in certain types of
cancer, most notably in breast cancer. The HER2 protein is encoded by the
ERBB2 gene, and it is part of a family of human epidermal growth factor receptors involved in various cellular processes.
How is HER2 related to cancer?
In the context of cancer, HER2 is significant because its overexpression can lead to aggressive tumor growth. Approximately 15-20% of breast cancers are classified as HER2-positive, meaning they have higher than normal levels of HER2 protein or an increased number of copies of the ERBB2 gene. This overexpression is linked to a higher risk of
metastasis and a poorer prognosis in the absence of targeted therapy.
What treatments target HER2-positive cancers?
Several targeted therapies have been developed to treat HER2-positive cancers. The most well-known is
trastuzumab (Herceptin), a monoclonal antibody that binds to the HER2 protein and inhibits the growth of cancer cells. Other treatments include
pertuzumab,
lapatinib, and
ado-trastuzumab emtansine (Kadcyla). These therapies have significantly improved outcomes for patients with HER2-positive breast cancer, transforming what was once considered a poor prognosis into a more manageable condition.
What are the side effects of HER2-targeted therapies?
Like all cancer treatments, HER2-targeted therapies can have side effects. Common side effects of trastuzumab include fever, nausea, fatigue, and headaches. More serious but less common side effects include
cardiotoxicity, which can lead to heart failure, especially when trastuzumab is combined with certain chemotherapy drugs. Patients receiving HER2-targeted therapy are monitored closely for heart function to manage this risk.
Are there new developments in HER2-targeted therapies?
Research into HER2-targeted therapies is ongoing, with several promising developments. New drugs and combinations are being tested in clinical trials to improve efficacy and reduce side effects. One such advancement is the development of
antibody-drug conjugates (ADCs), which combine an anti-HER2 antibody with a cytotoxic drug to deliver targeted chemotherapy directly to cancer cells. Additionally, research is exploring the role of HER2 in other cancers, such as gastric and lung cancer, to expand the potential applications of HER2-targeted therapies.
What is the prognosis for HER2-positive cancer patients?
The prognosis for patients with HER2-positive cancer has improved significantly with the advent of targeted therapies. Before these treatments were available, HER2-positive breast cancer was associated with a more aggressive disease course and worse outcomes. However, with therapies like trastuzumab, the outlook has improved markedly, with many patients achieving long-term remission. The prognosis varies based on individual factors, including the cancer stage and response to treatment, but overall, the introduction of HER2-targeted treatments has been a significant advancement in cancer care.
