However, in contrast to enrichment of CXCR4+ T cells in glioblastoma, the greater abundance of CXCR4 on these cells may reflect redundancy of this axis in tumour infiltration as ligation of CXCR4 by CXCL12 results in receptor internalisation and desensitisation (46). The gene discussed is CXCL12; the disease is glioblastoma.