We impose no-flux boundary condition on all the remaining variables:NofluxforC,Tr,D,I2,I12,Tα,Tβ,PA,A4,andSatr=R(t);(19)it is tacitly assumed here that CTLA-4 become actives only after the T cells are already inside the tumor. This evidence concerns the gene CTLA4 and neoplasm.