CTLA4 and posterior cortical atrophy: High frequencies of PD-1+ and CTLA-4+ CD4+ T cells and of differentiated CD8+ T cells, along with low frequencies of Treg cells and differentiated CD4+ T cells have been shown to correlate with improved OS following treatment with the GVAX vaccine (GVAX vaccine is a cellular vaccine consisting of two human PCa cell lines, LNCaP (CG8711) and PC-3 (CG1940), which have been transduced with an adeno-associated viral vector to secrete GM-CSF) in combination with Ipilimumab [45].