IL6 and chromophobe renal cell carcinoma: For the case of anti-CRCC efficacy, the IL-6 level can be used as a prognostic factor of CRCC and we use a similar expression for representation of the degree of anti-CRCC efficacy, i.e., we define the anti-CRCC efficacy Ec(t) to be the reciprocal for the IL-6 level at time t, i.e., Ec(t)=fcL(t) where fc is a scale factor.