Tregs in the PCa TME constitutively express the interleukin 2 (IL2) receptor, CD25, the gene Forkhead box protein P3 (Foxp3), along with the immune checkpoints CTLA4, inducible T cell co-stimulator (ICOS), LAG3, TIM3, OX40, and 4-1BB (59) (Figure 1B). The gene discussed is ICOS; the disease is posterior cortical atrophy.