3.4 kb mitochondrial DNA deletion for use in the detection of cancer

A method of detecting a cancer in an individual, the method comprising:

• a) obtaining a biological sample from the individual;
• b) quantifying the amount of mtDNA in the sample having a deletion in the nucleic acid sequence spanning approximately residues 10744 and 14124 of the mtDNA genome, wherein the step of quantifying comprises contacting the sample with a pair of amplification primers and amplifying a target region of mtDNA that is indicative of the deletion, wherein a first primer of the pair of primers is adapted to bind to a region of the mtDNA comprising a splice joining opposite ends of the mtDNA sequence after removal of the deletion;
• c) comparing the amount of mtDNA in the sample having the deletion to the amount of the deletion in a reference sample of mtDNA wherein the reference sample is from a known non-cancerous tissue or body fluid or from a known cancerous tissue or body fluid;
• wherein if the reference sample is from a known non-cancerous tissue or body fluid, then an elevated level of the deletion in the biological sample compared to the non-cancerous reference sample is indicative of cancer and if the reference sample is from a known cancerous tissue or body fluid sample then an equivalent or elevated level of the deletion in the biological sample compared to the cancerous reference sample is indicative of cancer.