CXCR4 and neoplasm: Such a dramatic effect on the intratumoral T cell compartment function is reflected in a study by Elda Righi (226) where CXCR4 antagonist AMD3100 by favorably modulating the intratumoral Teff/Treg ratio 6-fold, created a phenotype reminiscent of two studies that—although in different contexts—depleted intratumoral T-regs which highly significantly improved cytotoxic T-cell function in the tumor tissue and prolonged survival (234, 235).