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Many women who have breast cancer legitimately complain that treatments are as bad as the disease. A new method of predicting the prognosis of breast cancer, however, can tell women and their doctors whether a side effects-prone method of treatment is likely to lead to remission from the disease.
The Predictive Power of Metagenes
The new understanding of treatment outcomes in breast cancer stems from an observation that groups of genes, known as metagenes, tend to be "switched on" together in different forms of cancer. Prior research had found that in every form of cancer, there is a period in which chromosomes, the long strands of DNA in the nucleus of every cell, tend to be uniquely unstable and prone to making errors in the coding of proteins that the cell makes to regulate itself.
In addition to chromosomal instability, in different kinds of cancer, there is also a period of "mesenchymal transition." This fancy term refers to a period in which cancer cells become "unglued" from the tissues in which they were created and migrate to other parts of the body. Cancer cells feed on more and more sugar and have to absorb more and more sodium. Sodium ions are positively charged. This builds of a positive charge inside the cancer cell that neutralizes the negative charge on its outer membrane that keeps in anchored in place.
And scientists are also aware of metagenes that regulate a process called lymphocyte-specific immune recruitment. It's natural for the immune system to attack cancer cells, but some cancer cells develop methods to deactivate the specific white blood cells that would destroy them.
These three characteristics of metagenes apply to most kinds of cancer that form solid tumors. Of course, they aren't the only genes that scientists measure to assess the value of treatments for cancer.
Cancer Biomarkers and Choosing the Right Therapies
For several decades, doctors have been able to measure specific kinds of protein "biomarkers" to determine whether a specific treatment would be beneficial for a specific patient. A biomarker is a specific protein that appears in blood, tissue, or body fluids that only occurs during a specific disease process. Probably the best-known cancer biomarker in breast cancer is ER, the estrogen receptor marker, which tells whether or not breast cancer growth is fueled by estrogen, and whether estrogen-receptor antagonists, drugs such as tamoxifen, which prevent "docking" by estrogen on breast cancer cells, might prevent the progress of the disease. Other breast cancer biomarkers include:
- HER-2, human epidermal growth factor receptor 2, which indicates whether blocking the growth of breast tissue might stop the disease, and
- BRCA1 and BRCA2 markers, which tell women and their doctors whether they have genes that repair breast cell DNA and prevent cancer.
The new, metagenetic predictive algorithm does not replace these older tests. It only gives doctors additional information about the staging of cancer, telling them whether the emphasis should be on preventing the mutations that lead to new cancers, or stopping the spread of already-existing cancer beyond the breast, or bolstering the immune system so it can fight cancer even though it has already spread.