Determining cancer risk: the evolutionary multistage model or total stem cell divisions?

Area of Science:

• Evolutionary biology
• Cancer research
• Genetics

Background:

• The total number of stem cell divisions (TSCD) model hypothesizes intrinsic cancer risk.
• The multistage model has historically explained cancer origins.
• Discrepancies exist in understanding cancer frequency and its determinants.

Purpose of the Study:

• To test the validity of the TSCD model against an evolutionary multistage model of carcinogenesis (EMMC).
• To determine the most accurate model for interpreting cancer incidence worldwide.
• To assess the implications of these models for understanding cancer risk factors.

Main Methods:

• Applied three statistical tests to worldwide cancer incidence data.
• Compared predictions of the TSCD model with those of the EMMC.
• Evaluated models based on their ability to explain cancer frequency and distribution.

Main Results:

• All three tests supported the EMMC.
• The TSCD model was contradicted by the data.
• EMMC predictions align with cancer incidence in large, rapidly dividing tissues late in life.

Conclusions:

• The EMMC provides a more robust framework for understanding carcinogenesis.
• The TSCD model's conclusions regarding 'bad luck' versus other factors are undermined.
• Cancer suppression mechanisms in animals may offer insights for human cancer prevention.