CX3CL1 and central nervous system cancer: By quantitative RT-PCR we detected high levels of CXCL16 and CX3CL1 in human glioma, neuroblastoma, colon carcinoma, lower levels in breast cancer cells, and LOX melanoma cells produced very low or non-detectable mRNA amounts (Figure 1 upper panel; Δ CT in logarithmic scale, thus a 3.3 higher Δ CTvalue indicates a 10-fold lower expression).