#Cancer
Cancer
Cancer is the runaway reproduction and growth of cells, unbound by normal constraints (i.e. stop it you jerk, we're all in this together). In a vague general sort of way it's caused by cells deciding that the environment they're living in isn't conducive to cooperation and it reverts to winner take all (that is, I'm in this for me and my daughter cells). All the instructions for being a single-celled form of life is still in our DNA, it's just turned off so that cells specialize in order to cooperate together. Turn them back on again through some trigger and you get cancer.
Magical healing could potentially be viewed as a rapid increase in typical cellular life-cycle. And if the conditions are no longer viewed as mutually beneficial by the individual cells (i.e. the prisoner's dilemma equation starts looking better and better if the cell Defects rather than Cooperates) then they could be spurred towards being cancerous instead.
And cancer would just eat that healing magic right up. Yes please make me a healthier cell!
