CXCR4 and neoplasm: When tumour cell expression of high and low CXCL12 was compared with high and low CXCR4 expression (Figure 2C), in patients who showed both low CXCL12 and CXCR4 expression 32 of 235 patients (32%) had the best survival of 82 months, and patients with high CXCL12 and low CXCR4 displayed the worst survival, with 14 of 235 patients (33%) having a survival time of only 39 months.