You overcame Cancer 5 minutes ago.

Your immune system is constantly killing one of your cells to prevent cancer. It does this by stopping it from becoming a cancerous cell and saving your life. The vast majority of cancerous cells you develop will be killed without you ever knowing, as they are parts of yourself that start to behave as individuals even if it hurts you. What is cancer and how does your body fight it every day? Cancer is when normal cells become corrupted and start multiplying uncontrollably. It can emerge from any type of cell in your body, so there is not just one but hundreds of types of cancer. Some grow slowly, others are aggressive, and still, others can be treated effectively but may still result in death.

Evolution

The evolution of cells over billions of years has resulted in cells that are both ancient and new. Over time, cells have adapted to survive in a hostile environment by specializing and cooperating. However, this cooperation comes at a cost- some cancer cells become individualistic and stop contributing to the collective. Your body can tolerate a few rogue cells but when cancer cells grow in number, they can start to take away vital resources needed for survival, compete for space, and damage tissue they were once part of.

Many cells in our bodies carry out their programs blindly, without realizing they might be causing harm. That's because cancer cells go through a lot of mutations every day - many of which are benign. However, sometimes a mutation causes cancer to develop. DNA is responsible for the instructions that tell cells what to do; when it gets corrupted, the result can be dangerous and destructive activity. Mutations happen constantly throughout our lives - mostly without us even realizing - and most are corrected quickly or don't have any lasting impacts.

Over time, our cells can accumulate errors in their DNA as they replicate, which can lead to an increased risk of developing cancer. While certain factors like smoking and exposure to harmful substances can increase this risk, many cancer cases arise simply due to chance. Certain genes, called tumor suppressor genes (TSGs), play a crucial role in preventing abnormal cell growth, and when these genes become damaged or mutated, cancer cells can develop. While we can take steps to reduce our risk of cancer, some level of DNA damage is a natural part of aging, and it's important to take care of our bodies to reduce our risk of illness and enjoy a healthy life.

TSGs

Tumor suppressor genes (TSGs) have several functions, including repairing DNA errors and preventing normal cells from multiplying too quickly. If TSGs become damaged, cells may forget how to repair themselves and could multiply uncontrollably. The second important mutation that can lead to cancer involves oncogenes. These genes control rapid cell growth and division, which is necessary during fetal development. However, once a sufficient number of cells are formed, these genes are turned off. When oncogenes become activated later in life, they can cause cells to rapidly multiply, leading to cancer.

When oncogenes become corrupted, they can activate and cause cells to rapidly multiply. The third important mutation involves genes that control cell suicide, or apoptosis. Most cells undergo apoptosis when they accumulate too much damage, but if these genes become damaged, cells can continue to live on despite being corrupted. If a cell loses the ability to fix genetic mistakes, fails to undergo apoptosis, and begins to grow rapidly, it can develop into a young cancer cell.

Early-stage cancer cells can still be relatively weak and easy to kill, but if they continue to mutate and multiply, they can become more resistant to the body's immune defenses. The immune system constantly searches for and destroys corrupted cells, but it can be challenging to identify cancer cells that look similar to healthy ones.

The immune system has a clever way of identifying and distinguishing between healthy cells and corrupted cells, including cancer cells. This system involves MHC class I molecules, which act as a display window for cells to showcase the proteins they are producing.

Cells take small samples of the proteins they make and display them on the MHC molecules, constantly refreshing the selection to keep an up-to-date picture of their activities. The immune system has a library of highly dangerous proteins that should not be produced by healthy cells. It has billions of specialized cells called T cells that are designed to recognize specific proteins.

When a T cell sees a forbidden protein in an MHC display window, it knows that the cell is corrupted and immediately kills it. This system allows the immune system to identify and destroy corrupted cells, including those that have become cancerous.

The immune system's reliance on MHC class I molecules has a flaw: cancer cells can mutate to stop producing them, rendering themselves invisible to T cells. However, evolution has provided a solution in the form of Natural Killer Cells, which patrol the body checking for cells without MHC class I molecules. The absence of these molecules signals that the cell is hiding something and must be killed. This approach covers all bases, as T cells search for the unexpected while Natural Killer Cells look for the absence of the expected.

Cell Killer

The Natural Killer Cell is always ready to attack, making it even more impressive. It roams your body, scanning cell after cell, to kill anything that looks suspicious. Your healthy cells must persuade it that they do not deserve to die, and having MHC class I molecules is one way to do so.

MHC class I molecules serve as a marker for healthy cells, signaling to the Natural Killer Cells that they should not attack. By constantly displaying their protein contents, healthy cells reassure the Natural Killer Cells that they are functioning correctly and do not pose a threat.

In contrast, cancer cells often hide their MHC class I molecules or display the wrong proteins, indicating that they are no longer healthy. This is when the Natural Killer Cells spring into action, recognizing the absence of MHC class I molecules and killing the cancer cells.

In summary, while the human body is well-equipped to detect and eliminate young cancer cells through the action of T cells and Natural Killer cells, sometimes cancer cells mutate and become more resistant to the immune system's attacks. Cancer can be seen as an ongoing arms race between cancer cells and the immune system. However, promising cancer-fighting therapies such as cancer vaccines, engineered T cells, and Natural Killer cells are currently being developed and may eventually lead to the elimination of cancer. While the war against cancer is not yet won, progress is being made towards a cancer-free future.