Early Detection of BRCA Gene Mutations and Tackle the Refractory Triple-Negative Breast Cancer

Date:2020-10-07
Triple-Negative Breast cancer is well-known as the most difficult breast cancer to treat. This type of breast cancer accounts for 10% to 15% of the global breast cancer cases and the age of having this disease is often under the age of 40, which is lower than the general incidence of cancer. Since there wasn’t any target drug in the past, treatment was extremely difficult. Besides, the cancer cells of triple-negative breast cancer are easier to metastasize, it has a higher recurrence rate with higher malignancy and has larger tumors. This will be an unprecedented challenge for patients who are diagnosed with triple-negative breast cancer.

Why is Triple- Negative Breast Cancer Difficult to Treat?

Triple-negative breast cancer
Triple-Negative Breast Cancer (TNBC) refers to breast cancer that does not express the genes for either Estrogen receptor (ER), Progesterone Receptor (PR) and Human epidermal growth factor receptor 2 (HER2). If the patient is diagnosed with Estrogen or Progesterone receptor type cancer, hormone therapy can be used for treatment; similarly, if the patient is diagnosed with epidermal growth factor receptor breast cancer, they can be treated with anti-HER2 targets therapy. Hence, if the patient is diagnosed with TNBC, both hormonal and target therapy will be ineffective, most of the patients will be forced to choose chemotherapy. Chemotherapy has a huge side effect than other treatments, which causes triple-negative breast cancer recognized as the most difficult breast cancer to treat.

Triple-negative breast cancer is aggressive cancer. This type of breast cancer is easily metastasizing. The cancer cells grow are faster than other breast cancer and have a poor prognosis. Once the cancer cells start to spread to the surrounding organs, it will be much difficult for later treatment. Besides, patients diagnosed with triple-negative breast cancer often develop the disease under a relatively young age, 40. Even if patients have undergone treatment, there is still a high recurrence rate in the first 5 years and hence, it increases the death rate of this cancer type. As a result, patients often lose confidence in the treatment and choose to abandon later therapy.

The Hidden Breast Cancer Killer: BRCA Mutated Gene

The most commonly mutated gene in breast cancer is BRCA 1 and BRCA 2. About 10% to 15% of triple-negative breast cancer patients carry the BRCA mutated gene [1]. 57% of BRCA 1 mutation breast cancers and 23% of BRCA 2 mutation breast cancer are triple-negative [2], hence, if possible, to detected BRCA gene mutation at an early stage, patients can be treated before the onset of the disease.

BRCA genetic testing not only has an obvious therapeutic effect on a triple-negative breast cancer patient but also has a great value of prevention and guidance for patients’ families. Triple-negative breast cancer, like other breast cancers, can be caused by heredity. BRCA 1&2 genes mutation can be inherited from either parent, there is a 50% chance of inheriting the mutated gene to the next generation. Perform targeted preventive measures at an early stage can effectively control and reduce the onset of breast cancer, especially to reduce the risk of the onset of triple-negative breast cancer.

Combination of Genetic Testing with Targeted Therapy to Improve Treatment Success Rate

BRCA gene are mainly responsible for repairing damaged DNA or destroy cells if DNA cannot be repaired, and targeted drugs therapy can destroy cancer cell from preventing repairing damaged DNA of the cancer cells. The latest research has found that PARP (Poly ADP-ribose polymerase) inhibitors can be effectively used to treat triple-negative breast cancer. When the DNA in cancer cells is damaged, it needs PARP to be repaired. PARP inhibitors are used to prevent the repair function of PARP, hence, the cancer cells will die due to the repair function were inhibited.

Studies have shown, compare with chemotherapy, taking PRAP targeted drug therapy can reduce the size of the tumor. An effective way to control the disease and improve the survival rate of patients can be done if PARP inhibited drug is taken at an early stage. Besides, the use of drug-targeted therapy can also greatly reduce side effect and decrease the pain of the patients during treatment.

Although triple-negative breast cancer is difficult to treat, if patients combine genetic testing with drug targeted therapy, through BRCA 1/2 genetic testing at an early stage, the potential risk of the onset of breast cancer can be reduced. In other words, the chance of successful treatment will be greatly increased. Therefore, there will be no need to worry about the ineffective treatment of triple-negative breast cancer.

Reference:
[1] American Cancer Society https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/types-of-breast-cancer/triple-negative.html

[2] Atchley DP, Albarracin CT, Lopez A, et al. Clinical and pathologic characteristics of patients with BRCA-positive and BRCA-negative breast cancer. J Clin Oncol. 26(26):4282-8, 2008