BREAST CANCER - HER-2
HER-2 BREAST CANCER
What is it?
In Europe, HER-2 is called ERbB-2, but to keep it simple, I am going to refer to both as HER-2.
HER2 (Human Epidermal Growth Factor Receptor 2) is a gene that can play a role in the development of breast cancer. These genes are called oncogene.
I’ve read that mutated oncogenes can be inherited and are not inheritable, so do be careful with what you accept as a fact about this.
The HER-2 gene causes aggressive breast cancers to grow and spread faster than many other breast cancers.
THERE ARE TWO TYPES OF HER-2
- HER-2 POSITIVE – When HER-2 receptors cause an overproduction of themselves – an excessive replication and this is called an overexpression (or amplification) of protein. This causes the cells to mutate into cancer.
- HER-2 NEGATIVE – This occurs when the cancerous cells do not contain high levels of the protein HER-2. There are many treatment options available for this type of breast cancer, but the prognosis can vary.
HER-2 POSITIVE
HER-2 positive occurs when there are too many receptors present. Receptors are like light switches sitting on the surface of the breast cell. In the case of HER-2 positive, the light switch is switched to the permanent ‘on’ position which causes the speed and spread of cancer cell growth. Fortunately, HER-2 positive is responsive to treatments that target these receptors.
THIS IS WHY IT’S ABSOLUTELY CRUCIAL THAT YOU ASK FOR YOUR RECEPTOR STATUS BECAUSE IT WILL DEFINE YOUR COURSE OF TREATMENT.
Once you’ve had your biopsy, your breast surgeon will know your receptor status, a few days later which will be either,
- Estrogen positive or negative
- Progesterone positive or negative or,
- HER-2 positive or negative
If you have HER-2 positive breast cancer, the next thing to ask your oncologist is whether you should have chemo before surgery.
The main form of treatment for HER-2 is chemotherapy and immunotherapy (Chemo plus Herceptin or similar drug). This pairing now dramatically improves survival.
For indigenous African heritage women especially in the Caribbean and many parts of Africa, the problem comes down to the cost of medication, especially for Herceptin since it remains extremely expensive. Some countries have resorted to giving women Tamoxifen for HER-2 breast cancer because of the high cost of immunotherapy – Herceptin. Tamoxifen is a much cheaper and older type drug for treating Estrogen related breast cancer. If Tamoxifen was effective against HER-2 positive, Herceptin would never have needed to exist.
TRASTUZUMAB (HERCEPTIN)
Trastuzumab helps block cancer cells from receiving chemical signals (the receptors or proteins) that communicate the spur of growth. It does this by attaching itself directly to the HER-2 protein, thereby blocking incoming growth signals. Trastuzumab was the first drug approved to specifically target the HER-2 protein. It was a game-changer in the treatment of HER-2-postive breast cancers.
- HER-2-Positive (HER2+) Breast Cancer: Black Women Receive Targeted Therapy Less Frequently Than White Women – A global pattern.
- HER2+ prevalence was higher in stage I and II Caribbean patients than among the 1,517 reported African American or Caucasian patients (p=0.0001). The reason for this difference is not clear; confirmation from additional studies of Caribbean patients is needed. (2021 HER2 negative and has low levels of the protein Ki-67, which helps control how fast cancer cells grow. American Society of Clinical Oncology).
- It’s difficult to state the prevalence of HER-2 positive breast cancer in African ancestry because of the paucity of evidence in research and reliable data. Given HER-2 positive is an extremely aggressive breast cancer and given aggressive cancers such as TNBC, are disproportionately associated to women of African heritage, it’s entirely speculative to suggest HER-2 positive maybe higher than the 20% prevalence rate reported in White European women.
- Certainly, it can be said from many medical/social studies that racial disparities in late-stage diagnosis and primary treatment persist irrespective of breast cancer subtypes for African heritage women.
HOW IS HER2 DETECTED?
- Immunohistochemistry (IHC) measures the amount of HER2 protein present and is measured in the following way,
- A result of 0 is negative.
- A result of 1+ is also negative.
- A result of 2+ is considered equivocal (uncertain).
- A result of 3+ is positive.
- Fluorescent in situ hybridization (FISH) looks at the gene level for the number of copies of the gene present i.e. amplification. Sometimes, the results are inconclusive and may have to be repeated.
To properly diagnose your HER2 status, a biopsy is necessary – breast tissue is removed from the affected area and closely examined.
THINGS TO CONSIDER
- Chemotherapy might be better to do before surgery.
- HER-2 can be very responsive to chemotherapy and when it is, the tumor can shrink to something very small.
- This might mean the difference between a mastectomy and a lumpectomy.
- Targeted immunotherapy with Chemo, Herceptin and PERJETA. If you can stand it, the idea is to get ever particular and personal to your specific breast cancer – to shrink it and follow it. This is called neoadjuvant.
BREAST DOCTORS SHOULD ALSO CHECK:
- STAGE AT DIAGNOSIS. The more local the breast cancer (within your breast), the better that is for treatment particularly at the start of diagnosis. Metastatic breast cancer, which is cancer that has spread to distant areas of the body, is harder to treat.
- SIZE AND GRADE OF PRIMARY TUMOR. This determines how aggressive the cancer is.
- LYMPH NODE INVOLVEMENT. Cancer in the lymph nodes warns us that it could have spread to distant organs and tissues.
- HR and HER-2 ‘RECEPTOR’ STATUS. Targeted therapies can be used for HR-positive and HER2-positive breast cancers.
- OVERALL HEALTH. Other health issues that may complicate your treatment.
- RESPONSE TO THERAPY. It’s hard to predict whether a particular therapy will be effective or produce intolerable side effects. For example, some studies suggest racial disparities in the rate of cardiotoxicity of HER2-targeted therapies among women with early breast cancer – Black patients have a higher rate of cardiotoxicity and resultant incomplete adjuvant HER2-targeted therapy than white patients.
- AGE. Younger women and those over 60 may have a worse outlook than middle-aged women, except for those with stage 3 breast cancer.
