PETO S PARADOX

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Peto’s Paradox is the observation that larger animals, which have more cells and longer lifespans, do not have a higher incidence of cancer than smaller animals. This contradicts the expectation that more cells and more cell divisions should lead to a higher likelihood of cancerous mutations.

For example:

• Mice have a much higher cancer rate than whales, even though whales have vastly more cells.

• Humans and elephants have similar cancer rates, even though elephants have far more cells and live longer.

Possible Explanations:

1. Better Tumor Suppression Genes: Elephants, for instance, have extra copies of the TP53 gene, which helps prevent cancer.

2. Stronger DNA Repair Mechanisms: Larger animals may have evolved more robust DNA repair systems.

3. Lower Metabolic Rates: Larger animals often have slower metabolisms, which may reduce mutation rates.

4. Cellular Senescence and Growth Control: Their cells might be programmed to divide less or undergo apoptosis (self-destruction) more readily if damage is detected.

Peto’s Paradox highlights the complexity of cancer biology and suggests that nature has evolved protective mechanisms that could inspire cancer prevention strategies in humans.