Fig. 3

The abundance of mtDNA in clinical plasma samples categorized by cancer stage and type. A The abundance of mtDNA depending on cancer status for clinical centers U, N and A. B mtDNA fraction in lung cancer cases collected at clinical center N, categorized by TNM stage. The number of asterisks quantify the statistically significant difference between the different TNM groups with healthy controls using Kruskal–Wallis testing (*: p <  = 0.05, **: p <  = 0.01, ***: p <  = 0.001, ****: p <  = 0.0001, ns: non-significant). C mtDNA fraction in melanoma cases collected at clinical center A categorized by TNM stage. The number of asterisks quantify the statistically significant difference between the different TNM groups with healthy controls using Kruskal–Wallis testing (*: p <  = 0.05, **: p <  = 0.01, ***: p <  = 0.001, ****: p <  = 0.0001, ns: non-significant). D The abundance of mtDNA categorized by cancer type in samples processed under controlled pre-analytical conditions in collection center U. The number of asterisks quantify the statistically significant difference between the different cancer types with healthy controls using Kruskal–Wallis testing (*: p <  = 0.05, **: p <  = 0.01, ***: p <  = 0.001, ****: p <  = 0.0001, ns: non-significant)