What happens in breast cancer, exactly?

What is it?

Breast cancer is a cancer of the breast tissue. Most commonly it occurs in the cells associated with milk ducts. Cancer is characterized by the abnormal and uncontrollable growth of cells at the cost of the body’s other ones, and breast cancer is no exception to this.

Breast cancer is very common. It affects about 12% of women. Breast cancer accounts for around one fourth of all cancer diagnoses in women, and it’s much more common in developed countries than in the ones less so.

The chances of surviving breast cancer are heavily dependent on the stage at which it is diagnosed, and it’s impossible to say how an individual will do based on  statistics. At stage 0 or 1, however, the general chances of being alive after 5 years of being diagnosed are nearly 100%. At stage 4, when the cancer has spread to other parts of the  body, the chances have reduced to around 22%.

What causes it?

Breast cancer is caused by a mutation in a gene. This mutation can either be passed on from one generation to another, or it can come about during someones lifetime. Genetics is thought to be the main cause of 5-10% of cases. The most important risk factors are female sex and old age, and other significant ones include obesity, lack of physical activity, and excessive use of alcohol.

What happens during it?

Normal cells have a very specific function in the body in both time and space. They divide as many time as needed, stay in place by attaching to other cells, and commit suicide when it’s time for them to die. These mechanisms are regulated by messages from elsewhere in the body. Cells have protein receptors on their surfaces that are specialized in receiving a specific type of message and communicating it inside the cell. Genes are the “recipes” for proteins, and cancer arises when a faulty protein brought about by a genetic mutation disrupts the function of some receptor that is essential to the normal life cycle of a cell.

It is common, for example, that when a protective “switch” on the cell’s surface is turned off, the cell kills itself. In many forms of cancer, a mutation causes this switch to be permanently turned on, and because of this the cell is unresponsive to any such instructions.

Estrogen, the “female hormone”, has been associated with breast cancer. It is thought that when some forms of estrogen are broken down in the cell, dangerous molecules called radicals can emerge. These radicals are extremely reactive and will take a hydrogen atom or something of the like from anywhere they can find one. If this happens to be from the DNA, a mutation is likely to occur, and if the mutation happens in a unlucky location, cancer may develop. The more estrogen you have in your body, the more likely it is that a radical will find its way to your DNA and damage it.

When an original cancer cell has developed, it starts dividing very quickly. To do this it needs a large share of the body’s energy. This, together with the physical damage tumors can cause to other organs, is what makes cancer so dangerous. It literally drains the life out of you.

How can it be treated?

There are several effective lines of treatment for breast cancer, and they are often used together. The obvious one is surgery: if the tumor hasn’t spread to other parts of the body, the problem can be solved by simply removing the cancerous lump from the breast. Another common treatment is radiotherapy. Ironically, the aim of this is to produce more mutations: it is effective because cancer cells divide much more often than normal cells, and because DNA is much more likely to get damaged during cell division, more harm is done to cancer cells than to normal cells. Chemotherapy can also be very useful, as it blocks the mechanism of division and that way inhibits the growth of the tumor.


Sources: https://en.wikipedia.org/wiki/Breast_cancer, http://www.medicalnewstoday.com/articles/37136.php, http://www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-survival-by-stage, http://www.cumc.columbia.edu/publications/in-vivo/Vol2_Iss10_may26_03/, http://www.nhs.uk/Conditions/Cancer-of-the-breast-female/Pages/Treatment.aspx



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