CD4 and neoplasm: Intratumoral CD4+ Th2 cells and regulatory T cells (Tregs) are associated with reduced survival, whereas cytotoxic CD8+ T cells and CD4+ Th1 cells mediate tumor protection and are associated with prolonged survival in PDAC (Monte et al. 2011; Fukunaga et al. 2004; Hiraoka et al. 2006).