In accordance with previous findings53, SDF-1+ tumour cells were observed after radiation, but in this study, SDF-1 expression was higher in monocytes than in tumour stromal cells; this discrepancy may reflect a requirement for SDF-1 cleavage for cellular activity, as monocytic SDF-1 was not strongly detected with antibodies targeting the C terminus of SDF-1. The gene discussed is CXCL12; the disease is neoplasm.