system
Given the following post, respond as if you're commenting on Reddit:
human
Can small cuts lead to cancer?

Knowing that cancer cells carry mutant genes, some mutations occur during cell division and that cell division has a crucial role in repairing tissues / wound healing.
gpt
Yes, but you are missing the big point here. Why is cancer of the epithelium so common, while, for example, cancer of neurons so incredibly rare?

The answer is, your skin is in continuously turnover throughout your entire life. You do not see it, but old, dead skin cells are constant falling off of you, being replacted by fresh cells. Dust is actually partly constituted by dead skin.

Our barrier from the external world has to be continuously replaced and so cells must keep on replicating to supply new layers. But the non- regenerative neurons of the brain do not divide. You grow up and grow old with virtually the very same neurons in the central nervous system.

Now, wound healing certainly does lead to additional cell division, slightly increasing the risk. But the bulk of cell division happens passively in the epithelium, not just the skin, but also the gastrointestinal tract, as well as the lungs and, finally blood cells.