The present invention provides a method for determining the oxygen status of a cancer of an individual. The method comprise determining the transcriptional expression level of ADM (SEQ ID No:1), and/or at least one gene selected from ANKRD37 (SEQ ID NO.: 3), P4HA2 (SEQ ID NO.: 12), NDRG1 (SEQ ID NO: 10), SLC2A1 (SEQ ID NO:15), P4HA1 (SEQ ID NO.: 11), LOX (SEQ ID NO.: 9), C3orf28 (SEQ ID NO.: 6), BNIP3L (SEQ ID NO.: 5), BNIP3 (SEQ ID NO.:4), EGLN3 (SEQ ID NO.: 7), PDK1 (SEQ ID NO.: 13), PFKFB3 (SEQ ID NO.: 14), KCTD11 (SEQ ID NO.: 8), and/or ALDOA (SEQ ID NO.: 2), in a cancer sample. The transcriptional level is then correlated to the transcriptional level to at least one reference gene, and oxygen status 10 is then evaluated by comparing the correlated transcription level with a predetermined reference sample comprising cancer cells characterized by a high oxygen level.