Why is the importance of mitochondrial copy number in prostate cancer not well-understood: a systematic literature review


Year:

Session type:

Theme:

Sarah Willich

Abstract

Background

The number of mitochondrial DNA genomes found in cells has been shown to be significant in cancer including lung or breast cancer (Reznik et al. 2016). Therefore, it seemed likely that the same was the case in other cancer types such as prostate cancer (PCa). There have been studies investigating the role of mitochondrial DNA copy number (mtDNAcn) and PCa to investigate whether mtDNAcn could be used as a biomarker and diagnostic tool.

Method


Results

MtDNAcn seems to be reduced in prostate cancer tissue compared to unaffected prostate tissue surrounding the tumour (Kalsbeek et al. 2018) and this has been observed in other cancer types (Chen et al. 2016). However, this is contrary to earlier findings by Mizumachi et al. (2008) where they found an increase of mtDNA content in prostate cancer tissue compared to normal tissue. This difference was addressed by Kalsbeek et al. (2018) as a possible effect of varying approaches to tissue collection. When looking at peripheral blood leukocyte (PBLs) mtDNAcn of prostate cancer patients, elevated levels can be observed (Zhou et al. 2014; Chen et al. 2016; Moore et al. 2017). Xu et al. (2020) found that African American patients with lower mtDNA copy number in PBLs had a lower risk of biochemical relapse in a dose-dependent relationship. Zhou et al. (2014) even found a higher tumour burden (AJCC stages, Gleason score) to be associated with higher mtDNAcn in PBLs. Moore et al. (2017), however, were not able to replicate these findings.  

Conclusion

Overall, these results suggest that the significance of mtDNAcn role in the development and severity of prostate cancer cannot be determined yet due to these contradicting findings. A more standardised approach must be taken in tissue preparation and sample selection to allow for more conclusive findings in the future.  

Impact statement