Disclosed is the use of a therapeutically effective amount of a composition which inhibits the expression of the TMEM92 gene or which inhibits the function of the TMEM92 protein, in the manufacture of a medicament for the treatment of cancer. Also disclosed is a method for diagnosing cancer in a patient or for identifying a patient at risk of developing cancer, the method comprising: (a) determining an amount of a biomarker in a sample obtained from a patient, the biomarker comprising:- (i) a nucleic acid sequence comprising SEQ ID NO:1, or a functional fragment/variant that has at least about 70% nucleic acid sequence identity with SEQ ID NO:1, or a nucleic acid molecule which comprises said nucleic acid sequence or (ii) an amino acid sequence comprising SEQ ID NO:2, or a functional fragment/variant that has at least about 70% amino acid sequence identity with SEQ ID NO:2, or an amino acid molecule which comprises said amino acid sequence, optionally wherein the biomarker is a cancer biomarker selected from a prostate cancer biomarker, a non-small cell lung cancer biomarker and breast cancer biomarker.
