Associations between mitochondrial copy number, exercise capacity, physiologic cost of walking, and cardiac strain in young adult survivors of childhood cancer.

Purpose: Childhood cancer survivors are at risk for cardiac dysfunction and impaired physical performance, though underlying cellular mechanisms are not well studied. In this cross-sectional study, we examined the association between peripheral blood mitochondrial DNA copy number (mtDNA-CN, a proxy for mitochondrial function) and markers of performance impairment and cardiac dysfunction.

Methods: Whole-genome sequencing, validated by quantitative polymerase chain reaction, was used to estimate mtDNA-CN in 1720 adult survivors of childhood cancer (48.