What is the Difference Between HER2 Positive and HER2 Negative

The key difference between HER2 positive and HER2 negative is that HER2 positive is a type of breast cancer that has abnormally high levels of HER2 receptors, while HER2 negative is a type of breast cancer that does not have high levels of HER2 receptors.

Human epidermal growth factor receptor 2 is also called HER2 protein. It is found on the surface of breast cancer cells. It is usually involved in normal cell growth. However, too much of the HER2 receptor can cause some types of breast cancer to grow and spread aggressively. These are called HER2 positive breast cancer. However, HER2-negative breast cancers don’t have many HER2 receptors.

CONTENTS

1. Overview and Key Difference
2. What is HER2 Positive  
3. What is HER2 Negative
4. Similarities – HER2 Positive and HER2 Negative
5. HER2 Positive vs HER2 Negative in Tabular Form
6. Summary – HER2 Positive vs HER2 Negative

What is HER2 Positive?

HER2-positive breast cancer is a specific subtype of breast cancer characterized by breast cancer cells containing 40 to 100 times more HER2 receptors compared to HER2-negative breast cancer cells or normal breast cells. Therefore, both cancerous and noncancerous cells have HER2 receptors on their surfaces. However, the abundance of HER2 receptors fuels or triggers the growth of breast cancer.

Breast cancer cells are given a tumor grade at the time of diagnosis based on their appearance. Tumor grade 1 is the least aggressive, and tumor grade 3 is the most aggressive. HER2-positive tumors have a tumor grade of three. This means HER2-positive breast cancer tends to grow faster than tumors of lower grade. HER2-positive breast cancers are more likely to spread into lymph nodes; therefore, they have a high metastasis risk. Moreover, younger women, women of Asian or Hispanic descent, and individuals with ductal carcinoma in situ (DCIS) are more likely to have the HER2-positive state. Furthermore, if breast cancer has a high number of HER2 protein receptors, the treatment is based on targeted therapies through trastuzumab. This drug blocks the HER2 receptors and stops the HER2 protein from helping the breast cancer grow. In addition, chemotherapy and radiation therapy can also be used as treatment options for HER2-positive breast cancer.

What is HER2 Negative?

HER2-negative breast cancer is a form of breast cancer where the cancer cells do not produce an excessive amount of HER2 protein or receptor. Breast cancer that is HER2-negative tends to have a more favorable prognosis than HER2-positive breast cancer. Moreover, HER2-negative breast cancer is less aggressive, slow growing, and has less metastasis risk. Most breast cancers belong to the HER2-negative type.

HER2-negative breast cancer will be either HR-positive/HER2-negative or HR-negative/HER2-negative. HR refers to hormone receptors (estrogen and progesterone hormones receptors). If breast cancer is negative for HER2 receptors as well as both types of hormone receptors, these breast cancers are called triple-negative breast cancers. Furthermore, HER2-negative breast cancer can be treated through hormone therapy, chemotherapy, and radiotherapy.

What are the Similarities Between HER2 Positive and HER2 Negative?

• HER2-positive and HER2-negative are two different types of breast cancers.
• Both cancer types have HER2 protein
• Both cancer types can be diagnosed through mammography and immunohistochemistry (IHC).
• Both cancer types can be treated through chemotherapy and radiation therapy.

What is the Difference Between HER2 Positive and HER2 Negative?

HER2 positive is a type of breast cancer that has abnormally high levels of HER2 receptors, while HER2 negative is a type of breast cancer that does not have high levels of HER2 receptors. Thus, this is the key difference between HER2 positive and HER2 negative. Furthermore, HER2 positive is a very aggressive breast cancer, while HER2 positive is a less aggressive breast cancer.

The below infographic presents the differences between HER2 positive and HER2 negative in tabular form for side-by-side comparison.

Summary – HER2 Positive vs HER2 Negative

Breast cancer is a disease in which breast cells grow out of control. Women are predominantly affected by breast cancer. HER2-positive and HER2-negative are two different types of breast cancers. HER2 receptors or proteins are present in all HER2-positive as well as HER2-negative breast cancer cells. However, HER2-positive breast cancer has a high level of HER2 receptor, while HER2-negative breast cancers don’t have high levels of HER2 receptor. So, this is the key difference between HER2 positive and HER2 negative.

Reference:

1. “NCI Dictionary of Cancer Terms.” National Cancer Institute.

Image Courtesy:

1. “Positive immunohistochemistry of HER2 in invasive breast cancer” By Sandi Shen, Gaofang Xiao, Richang Du, Ningdong Hu, Xu Xia and Haibo Zhou – (2017). “Predictors of lymphovascular invasion identified from pathological factors in Chinese patients with breast cancer” Oncotarget 9 (2). DOI:10.18632/oncotarget.23503. ISSN 1949-2553. (CC BY 3.0) via Commons Wikimedia
2. “HER2 FISH algorithm” By Mikael Häggström, Reference: Wolff AC, Hammond MEH, Allison KH, Harvey BE, Mangu PB, Bartlett JMS (2018). “Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Focused Update”. J Clin Oncol 36 (20): 2105-2122. DOI:10.1200/JCO.2018.77.8738. PMID 29846122. (CC0) via Commons Wikimedia