CD4 and neoplasm: There is ample evidence supporting the hypothesis that tumors convert CD4+FoxP3− (Tconv) into CD4+FoxP3+ (iTreg) by tumor-derived signals, while others suggest that nTregs are recruited and/or expanded by the tumor (Nishikawa et al., 2003; Curiel et al., 2004; Valzasina et al., 2006; Liu et al., 2007b; Hindley et al., 2011).