Why Don't We All Have Cancer?

### Understanding the Human Body: Life, Death, and Cancer

this article is going to let you know Why Don't We All Have Cancer?

Since you started reading this article , over a million of your cells have died. It’s natural, so don’t worry! In fact, much of you is made up of dead material—your fingernails, hair, and the outermost layer of your skin are all dead. Every week, about 5.5 grams of dead skin sheds from your body. Surprisingly, research from Ohio State University reveals that 80% of the dust indoors is actually dead human skin.

However, most of you consists of living cells. Your body is a biological furnace, constantly burning food energy to move, breathe, and think. Remarkably, the heat from your hand can even power a Stirling engine! Your cells are active and divide millions of times daily. In fact, due to this relentless activity, perhaps we should call ourselves "persONs"—the "on" representing the ongoing process of life.

But here’s a mind-blowing fact: the process of cell division involves copying three billion nucleotides in DNA for each new cell. That’s a massive task! While our bodies do this efficiently, mistakes happen. Each time a cell divides, the DNA synthesis process makes about 120,000 errors. Some mutations may be beneficial, some harmful, and others neutral. Yet, when a mutation causes a cell to grow uncontrollably and spread, it can lead to cancer—a term that encompasses over 200 different diseases.

Mutations can occur randomly or be inherited and even induced by environmental factors. For instance, ultraviolet radiation from the sun can inflict genetic damage. A striking example includes a man who drove a truck for years, exposing one side of his face to more sunlight, leading to uneven skin damage. Similarly, a woman working by a window for 15 years showed pronounced environmental effects.

Given the multitude of risks our DNA faces, it’s astonishing that cancer isn’t more prevalent. Thankfully, our bodies have built-in mechanisms—like proofreading and mismatch repair—that correct over 99% of errors. As we age, these processes can weaken, leading to the accumulation of mutations, which can then result in cancer.

I want to express my gratitude to Cancer Research UK for their invaluable support in creating this episode. Their work is crucial as we discover new ways to prevent and treat cancer. Natural selection has its limitations, especially for diseases that manifest later in life, when reproduction has already occurred.

Historically, life expectancy was much lower. In the early 1600s in England, it was just 35 years. However, if you survived childhood, you could expect to live into your 60s. The selection shadow—where beneficial traits become common due to reproductive success—still influences human longevity.

Today, advancements in science and medicine are extending life. For instance, 40 years ago, only 25% of cancer patients lived ten years post-diagnosis. Now, that figure is 50%, with hopes it could rise to 75% in the next 20 years. Innovations like vaccinations against cervical cancer, improved sanitation, and anti-smoking campaigns are making a significant impact.

Cancer isn’t a single entity; it encompasses a wide range of diseases. There may never be one cure, but we are steadily discovering better prevention and detection methods. For example, advancements from the Large Hadron Collider have improved techniques for removing eye tumors.

When discussing cancer, we often use war-like terminology, but it’s more about managing a mutiny within our bodies. Natural selection has equipped us with tools; now it’s our responsibility to steer our health in a positive direction.