Mitochondrial DNA Copy Number Variations and Serum Pepsinogen Levels for Risk Assessment in Gastric Cancer

Association between microsatellite instability status, clinicopathological features and mitochondrial DNA amplification in patients with colorectal cancer

The relationship between BRAF-V600E mutations, mitochondrial DNA amplification and microsatellite instability-high (MSI-H) in colorectal cancer (CRC) has yet to be fully elucidated. The aim of the present study was to assess the association between the MSI status and BRAF-V600E gene mutations/clinicopathological features/mitochondrial DNA amplification in CRC. A non-interventional study analysis was performed using the clinicopathological features of 455 patients with CRC. Immunohistochemistry was used to evaluate four mismatch repair proteins (MutS homolog 2, MutS homolog 6, MutL homolog 1 and postmeiotic segregation increased 2), Ki-67 index, and programmed cell death protein 1 (PD-1) and programmed cell death-ligand 1 (PD-L1) expression. Additionally, PCR coupled with capillary electrophoresis were used to ascertain the MSI status. Moreover, amplification refractory mutation system-PCR was used to detect BRAF-V600E gene mutation and fluorescence in situ hybridization analysis was used to assess mitochondrial DNA. A total of 455 patients were divided into the MSI high (MSI-H) group (n=52) and microsatellite stability (MSS) group (n=403) based on their MSI status. Compared with the results of immunohistochemistry of four mismatch repair proteins, the consistency rate between mismatch repair protein deficiency and MSI was 94.23%. There were significant differences in PD-L1, primary tumor site, clinical stage, degree of differentiation, tumor size, lymph node metastasis and the occurrence of multiple primary tumors between the MSI-H group and MSS group (P<0.05 or P<0.001). However, there were no significant differences for sex, age, PD-1, Ki-67 expression and BRAF-V600E. The 24-60-month survival rate of the patients in the MSI-H group was significantly higher than that of those in the MSS group (P<0.05). Furthermore, the number of mitochondrial DNA was significantly amplified in the MSI-H group. In conclusion, the present study demonstrated that the combined detection of PD-L1 and MSI in patients with CRC can provide more accurate and effective guidance for personalized treatment.

Mitochondrial DNA Copy Number: Linking Diabetes and Cancer

Recent Advances: Various studies have suggested that mitochondrial DNA copy number (mtDNA-CN), a surrogate biomarker of mitochondrial dysfunction, is an easily quantifiable biomarker for chronic diseases, including diabetes and cancer. However, current knowledge is limited, and the results are controversial. This has been attributed mainly to methodology and study design. Critical Issues: The incidence of diabetes and cancer has increased significantly in recent years. Moreover, type 2 diabetes (T2D) has been shown to be a risk factor for cancer. mtDNA-CN has been associated with both T2D and cancer. However, it is not known whether mtDNA-CN plays any role in the association between T2D and cancer. Significance: In this review, we have discussed mtDNA-CN in diabetes and cancer, and reviewed the literature and methodology used in published studies so far. Based on the literature review, we have speculated how mtDNA-CN may act as a link between diabetes and cancer. Furthermore, we have provided some recommendations for reliable translation of mtDNA-CN as a biomarker. Future Directions: Further research is required to elucidate the role of mtDNA-CN in the association between T2D and cancer. If established, early lifestyle interventions, such as physical activity and diet control that improve mitochondrial function, may help preventing cancer in patients with T2D. Antioxid. Redox Signal. 37, 1168-1190.