Mitochondrial DNA haplogroups and somatic mutations are associated with lung cancer in patients from Southwest China

Mitochondrial DNA mutations play crucial roles in the pathogenesis and progression of human malignancies. Therefore, to determine whether maternal background or mitochondrial DNA somatic mutations were essential cofactors in the lung cancer of Chinese patients as well, the complete mitochondrial DNA displacement loop of the primary cancerous, matched para-cancerous normal and distant normal tissues for 79 Chinese patients with lung cancer were analyzed in this study. Our results indicated that the higher detected frequency of haplogroups prevalent in southern East Asia (53.16%; 42/79) versus those of northern East Asia in the studied population supported the southern East Asian characteristics of the Chinese lung cancer group. Further statistical analysis revealed that the haplogroups F* and G* contributed to the susceptibility to lung cancer in Chinese patients. In addition, by comparing sequences from different tissues of the same patients, a total of eight somatic mutations from six patients were detected. Combined with the fourteen somatic mutations identified in our previous study, the somatic mutation spectrum of the 79 Chinese patients with lung cancer was 25.32% (20/79). Our results suggest that mitochondrial DNA haplogroups and somatic mutations are associated with lung cancer in patients from Yunnan, Southwest China, and that somatic mitochondrial DNA mutations in the displacement loop can serve as potential biomarkers for clinical utility.