[patientzero]

While one can't really apply this model in comparisons between individuals, it tends to hold up in population models and is used to try to figure out how some species have evolved better defenses. For example:

https://www.nih.gov/news-events/nih-research-matters/how-ele...

For one individual they might have a number of genetic factors that in a world of perfect models could be used to calculate risk of an organ cancer per gram of the organ.. In the case of breast cancer there are studies on breast reduction and risk, but the one I found is not freely available..