Breast Cancer and Brain Metastasis

There are many different types of cancer, such as lung cancer and pancreatic cancer, each of which affects other parts of the body and targets different groups of people. One of the most dangerous cancers of all women is breast cancer. It's the second leading cause of death among women, and one out of every eight women in the United States is diagnosed with breast cancer in her lifetime. The main symptoms of breast cancer are lumps or dimples on the underarms and changes in the shape and texture of the nipples. 

Primary breast cancer is cancer that hasn't spread past the breast or underarm lymph nodes. This can be caused by various risk factors such as an unhealthy diet, smoking, and/or alcoholism. One of the leading causes of death among cancer patients is brain metastasis. They're cancerous growths that spread to the brain originating from a different part of the body. On average, about 19% of patients diagnosed with brain metastasis only live for one more year following diagnosis. 10%-30% of patients with metastatic breast cancer will develop brain metastases over the course of their disease due to the migration of cancer cells up to the brain. This leads to the development of the brain's tumors, with the five-year survival rating reaching barely 36%.

Metastatic Breast Cancer has a very low survival rate of 22% survival over five years. Hence, it is vital to find potential treatment and prevention methods. Moreover, due to Metastatic Breast Cancer, there are tremendous impacts on the individual socially, mentally, and emotionally; 70% of survivors experienced depression. Many face fear of cancer recurrence and body image issues resulting from a mastectomy (removal of breast tissue). In a study conducted by the National Center for Biotechnology Information (Series GSE125989), cancerous cells from 32 samples of primary breast cancer and brain metastasis were examined for the amount of RNA expression, its quantity, and quality in both types of cancers. The results showed that the amount of RNA expression in both cancers was reasonably similar and around the same range. However, this data has limitations as there were only 32 samples analyzed, the patients' age and gender were not listed, and the samples were all collected only from Japan. Due to these limiting factors, the data cannot be assumed for the whole population. Extracellular Matrix Disassembly is a process where the extracellular matrix breaks down. It is a critical step in the body's function, such as tissue remodeling, and involves the MMP2 and MMP14 genes. 

MMP2 allows for biological processes, and its most important function is to prevent excess blood vessels from being formed. This cuts of the supply that tumors rely on. MMP14 has a crucial role in the processing and activation of MMP2 and is a type 1 transmembrane protein. It is associated with metastasis and poor prognosis. MMP14 regulates the activity of multiple extracellular and plasma membrane proteins.

The genes MMP2 and MMP14 are critical in suppressing and preventing tumors. When the genes are downregulated, or when the body becomes resistant to these genes, the rate of developing brain cancer metastasis increases.

As a future study to test this hypothesis, two groups of people should be observed over a period of at least two years. One group should have downregulated MMP2 and MMP14 (people with breast cancer), and the other should have normally functioning genes (people without breast cancer). By performing this study, it can be proven that those with downregulated MMP2 directly correlate to developing brain cancer metastasis.

Future treatment options may include drugs to upregulate the MMP2 and MMP14; however, the only drugs that have been developed are those that downregulate the MMP genes. Immunotherapy is the most promising treatment for cancer in general. A type of immunotherapy called AB immunotherapy boosts the immune system by activating the MMP2.