It's not entirely clear how rare it is: http://en.wikipedia.org/wiki/Spontaneous_remission#Frequency_of_spontaneous_regression_in_cancer http://en.wikipedia.org

It's not entirely clear how rare it is: http://en.wikipedia.org/wiki/Spontaneous_remission#Frequency_of_spontaneous_regression_in_cancer http://en.wikipedia.org/wiki/Spontaneous_remission#Frequency...