HER2-Positive Breast Cancer

HER2-positive breast cancer usually happens due to the overgrowth of the HER2-positive cells with protein receptors in the breast area. Proteins are generally helpful in the growth, division and repair of the breast cells. Still, sometimes, due to some unusual reason, the overgrowth of these HER2-positive proteins results in the production of cancer cells in the breast. Moreover, HER2-positive breast cancer is more aggressive than the other types of cancer cells.

Causes of HER2-Positive Breast Cancer:

HER2-positive breast cancer usually affects younger women, but the actual reason behind this cancer is still unknown. Some of the risk factors of HER2-positive breast cancer are the following:

  • Obesity
  • Being female
  • Complications in childbirth or delivery
  • Use of cigrrate or Tobbacco
  • Sedentary lifestyle
  • History of receiving radiation therapy in the chest area
  • Family history of breast cancer

Symptoms of HER2-Positive Breast Cancer:

The symptoms of HER2-positive breast cancer are the following:

  • Swelling in breast
  • Irritation or dimpling in the skin of the breast
  • Inward turned nipples
  • Thickness or redness of breast skin or nipple
  • Breast or nipple pain
  • Discharge from nipple other than breast milk
  • Change in the shape of the breast
  • Lump in the breast that feels different from other areas of the breast or armpits

Diagnosis of HER2-Positive Breast Cancer:

During the diagnosis of HER2-positive breast cancer, the doctor will ask you about your medical and family history and conduct a physical exam to know the actual cause of the disease. Your doctor may also order tests such as Ultrasound and mammogram to see the size of the lump in the breast. In some cases, the doctor may also request a breast biopsy. He may also order the following tests for complete diagnosis:

  • During the inform Dual ISH test, stains have used to colour the sample of HER2 genes so that they could easily be counted under a microscope,
  • In the IHC test, specific antibodies are used to identify the HER2 protein in the sample of fresh or frozen breast cancer tissues that were taken for biopsy.
  • During the FISH Test, fluorescent pieces of DNA sticking to the HER2 genes are counted under an electron microscope.

Treatment of HER2-Positive Breast Cancer:

HER2 positive breast cancer is more aggressive than HER2 negative breast cancer. The treatment of HER2-positive breast cancer usually depends on the stage of cancer. Some of the following therapies will help treat breast cancer.


Surgery is one of the most important methods to treat breast cancer tumours. The need for breast-conserving surgery(removal of the tumour) or mastectomy(removal of the entire breast) usually depends on the size, location and the number of tumours present in the breast.

Radiation therapy:

Radiation therapy can be used to target any type of cancer cells that are left after surgery, and it is also helpful to shrink tumours. In Radiation therapy, high-energy X-rays are used to destroy the cells present in the breast. This therapy can be performed either externally through the machine or internally through needles and Catheters.


Chemotherapy is a systematic treatment in which powerful drugs are used that seek out or destroy cancer cells and prevent them from spreading or dividing. Chemotherapy is one of the best ways to treat HER2-positive breast cancer.

Targeted therapies:

Doctors use specific drugs in order to treat HER2-positive breast cancer; these drugs block the HER2 receptors and prevent the cells from further growing. These drugs are called Targeted therapies, and these drugs include:

Ado-trastuzumab emtansine(Kadcyla):

Ado-trastuzumab emtansine(Kadcyla) combines Trastuzumab and emtansine, delivering it directly to the HER2-positive cancer cells. It helps improve the survival of cancer patients and prevents breast cancer from returning. This method is usually applicable before surgery or after chemotherapy to prevent cancer cells from returning to the body.


Trastuzumab is the first drug approved to target cancer cells. It can block the growth of the cells by attaching itself directly to the HER2 protein and stopping the growth signals of the excessive cells. This drug can also be used with other treatments and help in long time survival of the patient.


Pertuzumab drug is also helpful in blocking the growth of cancer cells by attaching to the different parts of the HER2 protein. These drugs are often used with Trastuzumab for the treatment of breast cancer.


Neratinib is the drug that is given to adults after the completion of the treatment of breast cancer. This drug is often used with Trastuzumab, and the primary purpose of prescribing this drug is to prevent the recurrence of cancer cells in the body or stop the growth of these cells.


Lapatinib is a drug that can also be used to block the proteins that cause the uncontrolled growth of cells. It helps decrease the progression of the disease and combines hormonal treatment and oral chemotherapy to treat breast cancer.

Fam-trastuzumab deruxtecan(Enhertu):

This drug helps to combine Trastuzumab with deruxtecan. This drug helps prevent breast cancer from spreading to other body areas. It is usually given after two or three targeted therapies. It will also be given to people with HER2-positive breast cancer that cannot be removed through surgery.


Just like the drugs neratinib and lapatinib, it also works inside the cells and stops their uncontrolled growth. Tucatinib is used with capecitabine and Trastuzumab to treat advanced HER2-positive breast cancer, which cannot be treated through surgery.

Hormonal therapy:

If the cancer is hormone receptor-positive, certain drugs are used to stop the hormone estrogen from attaching to the cancer cells. These drugs that lower the estrogen level are Exemestane(Aromasin), Anastrozole(Arimidex) and Letrozole(Femara). The drugs that block the estrogen receptors are Tamoxifen(Nolvadex), Fulvestrant(Faslodex) and Toremifene(Fareston).

Reference list:

  • https://www.webmd.com/breast-cancer/her2
  • https://www.breastcancer.org/pathology-report/her2-status
  • https://www.healthline.com/health/breast-cancer/her2-positive-survival-rates-statistics
  • https://www.mayoclinic.org/breast-cancer/expert-answers/faq-20058066
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