An association analysis between mitochondrial DNA content, G10398A polymorphism, HPV infection, and the prognosis of cervical cancer in the Chinese Han population

Qualitative and quantitative changes in mitochondrial DNA associated with cervical cancer: A comprehensive review

Cervical cancer is the fourth most commonly diagnosed cancer in women and is considered a preventable disease, as vaccination and screening programs effectively reduce its incidence and mortality rates. Disease physiopathology and malignant cell transformation is a complex process, but it is widely known that high-risk HPV (hrHPV) infection is a necessary risk factor for cancer development. Mitochondria, cell organelles with important bioenergetic and biosynthetic functions, are important for cell energy production, cell growth, and apoptosis. Mitochondrial DNA is a structure that is particularly susceptible to quantitative (mtDNA copy number variation) and qualitative (sequence variations) alterations that are associated with various types of cancer. Novel biomarkers with diagnostic and prognostic value in cervical cancer can be evaluated to provide higher specificity and complement hrHPV molecular testing, which is the most recommended method for primary screening. In accordance with this, this review aimed to assess mitochondrial alterations associated with cervical cancer in clinical cervicovaginal samples, in order to unravel their possible role as specific diagnostic and prognostic biomarkers for cervical malignancy, and also to guide the understanding of their involvement in carcinogenesis, HPV infection, and disease progression.

Mitochondrial DNA content as a biomarker for oral carcinogenesis: correlation with clinicopathologic parameters

BACKGROUND

Mitochondrial genome (mtDNA) exhibits greater vulnerability to mutations and/or copy number variations than nuclear counterpart (nDNA) in both normal and cancer cells due to oxidative stress generated by inflammation, viral infections, physical, mechanical, and chemical load. The study was designed to evaluate the mtDNA content in oral potentially malignant disorders (OPMDs) and oral squamous cell carcinoma (OSCC). Various parameters were analyzed including its variation with human papillomavirus (HPV) during oral carcinogenesis.

METHODS

The present cross-sectional study comprised of two hundred patients (100 OPMDs and 100 OSCCs) and 100 healthy controls. PCR amplifications were done for mtDNA content and HPV in OPMDs and OSCC using real-time and conventional PCR respectively.

RESULTS

The relative mtDNA content was assessed quantitatively and it was observed that mtDNA was greater in OSCC (7.60±0.94) followed by OPMDs (5.93±0.92) and controls (5.37±0.95). It showed a positive linear correlation with habits and increasing histopathological grades. Total HPV-positive study groups showed higher mtDNA content (7.06±1.64) than HPV-negative counterparts (6.21±1.29).

CONCLUSIONS

An elevated mutant mtDNA may be attributed to increased free radicals and selective cell clonal proliferation in test groups. Moreover, sustained HPV infection enhances tumorigenesis through mitochondria mediated apoptosis. Since, mtDNA content is directly linked to oxidative DNA damage, these quantifications might serve as a surrogate measure for invasiveness in dysplastic lesions and typify their malignant potential.

Modeling of mitochondrial genetic polymorphisms reveals induction of heteroplasmy by pleiotropic disease locus 10398A>G

Mitochondrial (MT) dysfunction has been associated with several neurodegenerative diseases including Alzheimer's disease (AD). While MT-copy number differences have been implicated in AD, the effect of MT heteroplasmy on AD has not been well characterized. Here, we analyzed over 1800 whole genome sequencing data from four AD cohorts in seven different tissue types to determine the extent of MT heteroplasmy present. While MT heteroplasmy was present throughout the entire MT genome for blood samples, we detected MT heteroplasmy only within the MT control region for brain samples. We observed that an MT variant 10398A>G (rs2853826) was significantly associated with overall MT heteroplasmy in brain tissue while also being linked with the largest number of distinct disease phenotypes of all annotated MT variants in MitoMap. Using gene-expression data from our brain samples, our modeling discovered several gene networks involved in mitochondrial respiratory chain and Complex I function associated with 10398A>G. The variant was also found to be an expression quantitative trait loci (eQTL) for the gene MT-ND3. We further characterized the effect of 10398A>G by phenotyping a population of lymphoblastoid cell-lines (LCLs) with and without the variant allele. Examination of RNA sequence data from these LCLs reveal that 10398A>G was an eQTL for MT-ND4. We also observed in LCLs that 10398A>G was significantly associated with overall MT heteroplasmy within the MT control region, confirming the initial findings observed in post-mortem brain tissue. These results provide novel evidence linking MT SNPs with MT heteroplasmy and open novel avenues for the investigation of pathomechanisms that are driven by this pleiotropic disease associated loci.

Prediction of carcinogenic human papillomavirus types in cervical cancer from multiparametric magnetic resonance images with machine learning-based radiomics models

PURPOSE

This study aimed to evaluate the potential of machine learning-based models for predicting carcinogenic human papillomavirus (HPV) oncogene types using radiomics features from magnetic resonance imaging (MRI).

METHODS

Pre-treatment MRI images of patients with cervical cancer were collected retrospectively. An HPV DNA oncogene analysis was performed based on cervical biopsy specimens. Radiomics features were extracted from contrast-enhanced T1-weighted images (CE-T1) and T2-weighted images (T2WI). A third feature subset was created as a combined group by concatenating the CE-T1 and T2WI subsets. Feature selection was performed using Pearson's correlation coefficient and wrapper- based sequential-feature selection. Two models were built with each feature subset, using support vector machine (SVM) and logistic regression (LR) classifiers. The models were validated using a five-fold cross-validation technique and compared using Wilcoxon's signed rank and Friedman's tests.

RESULTS

Forty-one patients were enrolled in the study (26 were positive for carcinogenic HPV oncogenes, and 15 were negative). A total of 851 features were extracted from each imaging sequence. After feature selection, 5, 17, and 20 features remained in the CE-T1, T2WI, and combined groups, respectively. The SVM models showed 83%, 95%, and 95% accuracy scores, and the LR models revealed 83%, 81%, and 92.5% accuracy scores in the CE-T1, T2WI, and combined groups, respectively. The SVM algorithm performed better than the LR algorithm in the T2WI feature subset (P = 0.005), and the feature sets in the T2WI and the combined group performed better than CE-T1 in the SVM model (P = 0.033 and 0.006, respectively). The combined group feature subset performed better than T2WI in the LR model (P = 0.023).

CONCLUSION

Machine learning-based radiomics models based on pre-treatment MRI can detect carcinogenic HPV status with discriminative accuracy.

Roles of mitochondrial DNA in dynamics of the immune response to COVID-19

Mitochondria dynamics have a pivotal role in many aspects of immune function. Viral infections affect mitochondrial dynamics and trigger the release of mitochondrial DNA (mtDNA) in host cells. Released mtDNA guides the immune response towards an inflammatory response against pathogens. In addition, circulating cell-free mtDNA (ccf-mtDNA) is considered an invaluable indicator for the prognosis and severity of infectious diseases. This study provides an overview of the role of mtDNA in the dynamics of the immune response to COVID-19. We focused on the possible roles of mtDNA in inducing the signaling pathways, and the inflammasome activation and regulation in SARS-CoV-2. Targeting mtDNA-related pathways can provide critical insights into therapeutic strategies for COVID-19.

Molecular Pathology of Human Papilloma Virus-Negative Cervical Cancers

Cervical cancer is the fourth most common cancer in women worldwide and is predominantly caused by infection with human papillomavirus (HPV). However, a small subset of cervical cancers tests negative for HPV, including true HPV-independent cancers and false-negative cases. True HPV-negative cancers appear to be more prevalent in certain pathological adenocarcinoma subtypes, such as gastric- and clear-cell-type adenocarcinomas. Moreover, HPV-negative cervical cancers have proven to be a biologically distinct tumor subset that follows a different pathogenetic pathway to HPV-associated cervical cancers. HPV-negative cervical cancers are often diagnosed at an advanced stage with a poor prognosis and are expected to persist in the post-HPV vaccination era; therefore, it is important to understand HPV-negative cancers. In this review, we provide a concise overview of the molecular pathology of HPV-negative cervical cancers, with a focus on their definitions, the potential causes of false-negative HPV tests, and the histology, genetic profiles, and pathogenesis of HPV-negative cancers.

HPV-Negative Cervical Cancer: A Narrative Review

Cervical cancer (CC) is the fourth most frequent cancer in women worldwide. HPV infection is associated with the majority of CC cases, but a small proportion of CCs actually test negative for HPV. The prevalence of HPV among CC histotypes is very different. It has been suggested that HPV-negative CC may represent a biologically distinct subset of tumors, relying on a distinct pathogenetic pathway and carrying a poorer prognosis, than HPV-positive CCs. Although, the discordance in terms of sensitivity and specificity between different HPV tests as well as the potential errors in sampling and storing tissues may be considered as causes of false-negative results. The identification of HPV-negative CCs is essential for their correct management. The aim of this narrative review is to summarize the clinical and pathological features of this variant. We also discuss the pitfalls of different HPV tests possibly leading to classification errors.

Human Papillomavirus-Negative Cervical Cancer: A Comprehensive Review

Human papillomavirus (HPV) has been the leading cause of cervical cancer for over 25 years. Approximately 5.5–11% of all cervical cancers are reported to be HPV-negative, which can be attributed to truly negative and false-negative results. The truly HPV-negative cervical cancers are almost all cervical adenocarcinomas with unclear etiology. False HPV negativity can arise from histological misclassification, latent HPV infection, disruption of the targeting fragment, non-high risk HPV infection, and HPV testing methods. HPV-negative cervical cancers are often diagnosed at an advanced FIGO stage and have a poor prognosis; thus, the management of these cases requires greater attention.

Comprehensive Identification of the Human Secretome as Potential Indicators in Treatment Outcome of HPV-Positive and -Negative Cervical Cancer Patients

BACKGROUND

The aim of this work was to explore the novel and promising biomarkers for the diagnosis and prognosis of cervical cancer patients.

METHODS

The secretome of primary cervical tissues was extracted and then determined by the LC-MS/MS assay. The level of screened targets was confirmed using the RT-PCR and ELISA in cervical cancer tissue samples. The median expression level of certain targets was used as a cutoff value to divide the patients into 2 groups, and then the patients were followed up. The predictive abilities of the targets on the prognosis were further studied.

RESULTS

LC-MS/MS, together with bioinformatic analysis, demonstrated that totally 95 targets were dysregulated in cervical cancer. Among them, ECM2, KLK6, and MASP1 were increased in cervical cancer in a stage-dependent manner, whereas FGA was negatively associated with the stage of cervical cancers. Overall survival (OS) and disease-free survival (DFS) rates were significantly decreased in the KLK6 high group, whereas little difference was found between the high and low groups of other 3 cases. Univariate analysis of the 5-year OS and DFS revealed a significantly worse outcome for patients with KLK6 high tumors. In multivariate analysis, KLK6 remained a highly significant prognostic marker for OS and DFS. Combined survival analysis of KLK6 expression and the HPV infection revealed that KLK6highHPV(-) predicted the most poor OS rate and the KLK6lowHPV(+) group showed the best prognosis.

CONCLUSION

Through the secretome analysis, we identified a series of secreted proteins differentially expressed in the clinical cancer, among which KLK6 has the potential to become a promising biomarker for the diagnosis and prognosis of cervical cancer patients.

Prognostic significance of negative conversion of high-risk Human Papillomavirus DNA after treatment in Cervical Cancer patients

Objective: To evaluate the prognostic value of conversion of high-risk human papillomavirus (HR-HPV) status after treatment for cervical cancer.

Methods: A total of 112 cervical cancer patients with HR-HPV positivity without distant metastasis treated with surgery or radical concurrent radiochemotherapy were enrolled. HR-HPV status was analyzed before and after treatment and at the time point of recurrence or metastasis. Log-rank tests and Cox proportional hazard models were used to evaluate the association between conversion of HR-HPV status after treatment and survival.

Results: Eighty-four (75%) patients had negative conversion HR-HPV (ncHR-HPV) after treatment and twenty-eight (25%) were persistent positive HR-HPV (ppHR-HPV). The negative conversion rate was 75.8% in patients who received surgical treatment and 71.4% in patients who received radical concurrent radiochemotherapy. There was no significant difference between the two groups (χ²=0.000, P=1.000). There was no significant correlation between HR-HPV conversion after treatment with age (χ²=0.616, P=0.252), FIGO stage (χ²=0.051, P=0.823) and pathological type (χ²=0.000, P=1.000). Univariate analysis showed that treatment regimen and ncHR-HPV was closely related to progression-free survival (PFS) and overall survival (OS) of cervical cancer patients. Multivariate COX regression model showed that treatment regimen (HR=3.57, 95% CI: 1.57-8.11, P=0.002) and ncHR-HPV (HR=5.14, 95% CI: 2.32-11.46, P<0.001) were independent prognostic factors for PFS, while only ncHR-HPV (HR=12.56, 95% CI: 3.54-44.65, P<0.001) was an independent prognostic factor for OS. The presence of ppHR-HPV after treatment (χ²=14.827, P<0.001) was associated with recurrence and metastasis. Eleven of the patients with ncHR-HPV after treatment had recurrence or metastasis, and HPV reinfection was not detected in any of them.

Conclusion: ncHR-HPV after treatment in cervical cancer patients indicated better PFS and OS, while ppHR-HPV indicated worse prognosis and high risk of recurrence or metastasis. For patients with ncHR-HPV after treatment, continued HPV screening may not predict recurrence or metastasis. This study suggested that HR-HPV monitoring is necessary for ppHR-HPV patients after treatment but may not be for ncHR-HPV patients. However, further large and multi-center prospective studies should be performed to confirm these findings.

Role of Mitochondrial DNA (mtDNA) Variations in Cancer Development: A Systematic Review

mtDNA is the closed circular, ds-DNA present in mitochondria of eukaryotic cells and are inherited maternally. Besides being the power house of the cell, mitochondria are also responsible for the regulation of redox homeostasis, signaling, metabolism, immunity, survival and apoptosis. Lack of a 'Systematic Review' on mtDNA variations and cancers encouraged us to perform the present study. Pubmed', 'Embase' and 'Cochrane Library' databases were searched using keywords 'Mitochondrial DNA' OR 'mtDNA' OR 'mDNA' AND 'polymorphism' AND 'cancer' AND 'risk' to retrieve literature. Polymorphisms occupy first rank among mtDNA variations followed by CNV, MSI, mutations and hold a great potential to emerge as key predictors for human cancers.

Mitochondrial DNA copy number in cervical exfoliated cells and risk of cervical cancer among HPV-positive women

Background

Although human papillomavirus (HPV) infection has been regarded as the cause of cervical cancer in over 99% of cases, only a small fraction of HPV-infected women develop this malignancy. Emerging evidence suggests that alterations of mitochondrial DNA copy number (mtCN) may contribute to carcinogenesis. However, the relationship between mtCN and cervical cancer remains undetermined.

Methods

The current study included 591 cervical cancer cases and 373 cancer-free controls, all of whom were infected with high-risk HPV. Relative mtCN in cervical cancer exfoliated cells was measured by qRT-PCR assays, and logistic regression analysis was performed to compute odds ratios (ORs) and 95% confidence intervals (CIs). Interaction between mtCN and HPV types was assessed by using the Wald test in logistic regression models.

Results

HPV16, 18, 52, and 58 were the most common types in both case and control groups. Median mtCN in cases was significantly higher than that in controls (1.63 vs. 1.23, P = 0.03). After adjustment for age and HPV types, the highest quartile of mtCN was associated with increased odds of having cervical cancer (OR = 1.77, 95% CI = 1.19, 2.62; P < 0.01), as compared to the lowest quartile. A dose-response effect of mtCN on cervical cancer was also observed (P_trend < 0.001). The interaction between mtCN and HPV types was statistically nonsignificant.

Conclusions

In women who test HPV positive, the increase of mtCN in cervical exfoliated cells is associated with cervical cancer. This suggests a potential role of mtCN in cervical carcinogenesis.

Human Papillomavirus-related Cancers and Mitochondria

Although it has been established that persistent infection with high risk human papillomavirus (HR-HPV) is the main cause in the development of cervical cancer, the HR-HPV infection is also related with the cause of a significant fraction of other human malignancies from the mucosal squamous epithelial such as anus, vagina, vulva, penis and oropharynx. HR-HPV infection induces cell proliferation, cell death evasion and genomic instability resulting in cell transformation, due to HPV proteins, which target and modify the function of differents cell molecules and organelles, such as mitochondria. Mitochondria are essential in the production of the cellular energy by oxidative phosphorylation (OXPHOS), in the metabolism of nucleotides, aminoacids (aa), and fatty acids, even in the regulation of cell death processes such as apoptosis or mitophagy. Thus, mitochondria have a significant role in the HPV-related cancer development. This review focuses on the role of HPV and mitochondria in HPV-related cancer development, and treatments associated to mitochondrial apoptosis.

Immunoscore system combining CD8 and PD-1/PD-L1: A novel approach that predicts the clinical outcomes for cervical cancer

PURPOSE

Immunoscore was established to evaluate the prognosis of cancer patients. However, the feasibility of Immunoscore for the prognosis of cervical cancer remains unknown. To find other prognostic markers that contribute to immunological importance, immune checkpoint inhibitors targeting programmed cell death protein (PD-1), or its ligand, PD-L1, are of enormous interest. Our purpose is to investigate the expression of CD8 and PD-1/PD-L1 and their potential role in Immunoscore, supplementing the tumor/node/metastasis (TNM) classification of cervical cancer.

METHODS

Immunoscore was assessed according to the density of PD-1, PD-L1, and CD8 by immunohistochemistry. The association with overall survival and disease-free survival was assessed by the Kaplan-Meier method. To evaluate the effect of Immunoscore, a Cox proportional hazard regression classification was conducted. To compare the prognostic accuracies of Immunoscore and TNM staging, receiver operating characteristic curves were plotted.

RESULTS

Patients with PD-L1positive and PD-1high in immune cells had poorer overall survival and disease-free survival; however, PD-L1positive in tumor cells that infiltrated more CD8+ T cells were related to better overall survival and disease-free survival. These immune factors can be independent predictors for prognoses. According to these factors, a new Immunoscore system with priority in predicting prognoses was established. In receiver operating characteristic analysis for predictions of overall survival (the area under curve (AUC) = 0.833 vs. 0.766) and disease-free survival (AUC = 0.861 vs. 0.729), Immunoscore is more accurate than TNM staging.

CONCLUSIONS

Thus, this Immunoscore system is an accurate predictive marker, which can be an important supplement to TNM staging for cervical cancer.

Mitochondrial functions and melatonin: a tour of the reproductive cancers

Cancers of the reproductive organs have a strong association with mitochondrial defects, and a deeper understanding of the role of this organelle in preneoplastic-neoplastic changes is important to determine the appropriate therapeutic intervention. Mitochondria are involved in events during cancer development, including metabolic and oxidative status, acquisition of metastatic potential, resistance to chemotherapy, apoptosis, and others. Because of their origin from melatonin-producing bacteria, mitochondria are speculated to produce melatonin and its derivatives at high levels; in addition, exogenously administered melatonin accumulates in the mitochondria against a concentration gradient. Melatonin is transported into tumor cell by GLUT/SLC2A and/or by the PEPT1/2 transporters, and plays beneficial roles in mitochondrial homeostasis, such as influencing oxidative phosphorylation and electron flux, ATP synthesis, bioenergetics, calcium influx, and mitochondrial permeability transition pore. Moreover, melatonin promotes mitochondrial homeostasis by regulating nuclear DNA and mtDNA transcriptional activities. This review focuses on the main functions of melatonin on mitochondrial processes, and reviews from a mechanistic standpoint, how mitochondrial crosstalk evolved in ovarian, endometrial, cervical, breast, and prostate cancers relative to melatonin's known actions. We put emphasis on signaling pathways whereby melatonin interferes within cancer-cell mitochondria after its administration. Depending on subtype and intratumor metabolic heterogeneity, melatonin seems to be helpful in promoting apoptosis, anti-proliferation, pro-oxidation, metabolic shifting, inhibiting neovasculogenesis and controlling inflammation, and restoration of chemosensitivity. This results in attenuation of development, progression, and metastatic potential of reproductive cancers, in addition to lowering the risk of recurrence and improving the life quality of patients.

Is mitochondrial DNA copy number a good prognostic marker in resectable pancreatic cancer?

BACKGROUND

The aim of this prospective study was to investigate mitochondrial DNA (mtDNA) copy number in a group of resectable pancreatic cancer (PC) tumor tissues and adjacent normal pancreatic tissues, and to explore the correlation between the mtDNA content in tissues and the clinicopathological parameters and the overall survival.

METHODS

Relative mtDNA copy number was measured by the quantitative PCR-based assay. The tumors specimens (n = 43) originated from the patients with pathologically confirmed pancreatic ductal adenocarcinoma who did not receive any neoadjuvant systemic therapy. The adjacent normal pancreatic tissue samples (n = 31) were obtained from surgical margins.

RESULTS

mtDNA copy number was significantly lower in PC tissue (P < 0.001) compared to adjacent normal pancreatic tissue. Jonckheere-Terpstra trend testing indicated a statistically significant decrease in median mtDNA copy number across the differentiation (adjacent normal pancreatic tissue, low-grade, intermediate-grade, high-grade cancer), P < 0.001. However, the survival analyses failed to show a significant difference in survival between patients with high and low mtDNA copy number.

CONCLUSIONS

To the best of our knowledge, we provided the first evidence that mitochondrial DNA copy number was significantly lower in pancreatic cancer tissue (P < 0.001) compared to adjacent normal pancreatic tissue. Also, we demonstrated that mitochondrial copy number was not a significant marker for predicting prognosis in resectable pancreatic cancer.

Mitochondrial inheritance and cancer

Mitochondria are essential intracellular organelles that are responsible for energy metabolism, cell growth, and differentiation, redox homeostasis, oncogenic signaling, and apoptosis. These multifunctional organelles have been implicated in cancer initiation, progression, and metastasis, relapse, and acquired drug resistance due to metabolic alterations in transformed cells. Maternally inherited mitochondrial DNA (mtDNA) is thought to contribute to cancer development and prognosis and proposed as a therapeutic target for cancer treatment. In this review, we summarize the current knowledge of mtDNA alterations, with a specific focus on somatic changes, germline variants, haplogroups, large deletions, and mtDNA content changes associated with cancer susceptibility and prognosis. We also discuss the potential of mtDNA as biomarkers of cancer detection and targets of cancer treatment. Deeper understanding of the mechanisms underlying these associations requires further investigation.

Mitochondrial genome variation and prostate cancer: a review of the mutational landscape and application to clinical management

Prostate cancer is a genetic disease. While next generation sequencing has allowed for the emergence of molecular taxonomy, classification is restricted to the nuclear genome. Mutations within the maternally inherited mitochondrial genome are known to impact cancer pathogenesis, as a result of disturbances in energy metabolism and apoptosis. With a higher mutation rate, limited repair and increased copy number compared to the nuclear genome, the clinical relevance of mitochondrial DNA (mtDNA) variation requires deeper exploration. Here we provide a systematic review of the landscape of prostate cancer associated mtDNA variation. While the jury is still out on the association between inherited mtDNA variation and prostate cancer risk, we collate a total of 749 uniquely reported prostate cancer associated somatic mutations. Support exists for number of somatic events, extent of heteroplasmy, and rate of recurrence of mtDNA mutations, increasing with disease aggression. While, the predicted pathogenic impact for recurrent prostate cancer associated mutations appears negligible, evidence exists for carcinogenic mutations impacting the cytochrome c oxidase complex and regulating metastasis through elevated reactive oxygen species production. Due to a lack of lethal cohort analyses, we provide additional unpublished data for metastatic disease. Discussing the advantages of mtDNA as a prostate cancer biomarker, we provide a review of current progress of including elevated mtDNA levels, of a large somatic deletion, acquired tRNAs mutations, heteroplasmy and total number of somatic events (mutational load). We confirm via meta-analysis a significant association between mtDNA mutational load and pathological staging at diagnosis or surgery (p < 0.0001).

Sequence variations of mitochondrial DNA D-loop region in patients with acute myeloid leukemia

The aim of the present study was to explore variations of the displacement (D)-loop region in patients with acute myeloid leukemia (AML) and their possible associations with AML pathogenesis. Blood or bone marrow samples from 216 patients with AML (158 AML patients in the first stage, and 58 more patients with AML-M3 for further verification), and 146 healthy controls were collected. Sanger sequencing was performed for the D-loop region ranging between nucleotide (nt)15811 and nt 775. With the exception of mitochondrial microsatellite instability (mtMSI) variations, a total of 2,630 variations in 232 loci were identified with similar variation rates/person in patients with AML and controls when compared with the revised Cambridge reference sequence (8.54±2.14 vs. 8.77±2.15; P=0.366). A positive association between AML and variation-T152C was identified, which occurred more frequently in patients with AML compared with in controls [26.6 vs. 17.1%; P=0.048; odds ratio (OR), 1.752; 95% confidence interval (CI), 1.004-3.058]. Furthermore, T152C was identified to be associated with promyelocytic leukemia-retinoic acid receptor α(PML-RARα) and French-American-British AML subtypes, with a tendency to occur in patients with AML-M3. The AML-M3 sample size was extended by 58 cases, and it was identified that the T152C variation rate was significantly higher in patients with AML-M3 compared with that of controls (41.0 vs. 17.1%; P<0.001; OR, 3.228; 95% CI, 1.714-6.079). However, no association was identified between the T152C variation and clinical characteristics, or chemotherapy response in patients with AML-M3. In addition, the mtMSIs, including D310, mt514-523 (CA)_n and T16189C, demonstrated no association with AML risk. Together, the results of the present study suggest that the mitochondrial DNA D-loop region is high variable, and that T152C is associated with AML risk, particularly regarding the M3 subtype. T152C mayparticipate in AML pathogenesis and may be a diagnostic biomarker; however further studies with larger sample sizes are required in order to verify its value.

Prognostic value of HPV DNA status in cervical cancer before treatment: a systematic review and meta-analysis

Background

Human papillomavirus (HPV), has been recognized as an vital preliminary event in the oncogenesis of cervical cancer. But the prognostic value is not well defined, because of past studies showing conflicting results. So we conducted this meta-analysis to evaluate whether HPV DNA status was associated with prognosis in cervical cancer.

Materials and Methods

A total of 17 previously published eligible studies including 2,838 cases were identified and included in this meta-analysis. Positive HPV DNA was associated with good prognosis in patients with cervical cancer (overall survival [OS]: pooled hazard ratio (HR) = 0.610, 95% confidence interval (CI) = 0.457−0.814, P = 0.001; disease free survival [DFS]: pooled HR = 0.362, 95% CI = 0.252−0.519, P < 0.001). Furthermore, in subgroup analysis, the results revealed that the association between HPV DNA positive cervical cancers and better OS (pooled HR = 0.534, 95 % CI = 0.355–0.804, P = 0.003) in Mongoloid patients. Similarly, it existed in good OS (pooled HR = 0.628, 95 % CI 0.429−0.922, P = 0.017) and DFS (pooled HR = 0.355, 95% CI = 0.226−0.559, P < 0.001) in Caucasian patients.

Conclusions

HPV DNA status in cervical cancer may be a useful prognostic biomarker before carcinomas are treated. However, larger sample sizes and more comprehensive studies are required in the future studies to verify our findings.

Elevated Mitochondrial DNA Copy Number in Peripheral Blood and Tissue Predict the Opposite Outcome of Cancer: A Meta-Analysis

Previous studies have suggested that mitochondrial DNA (mtDNA) copy number was associated with cancer risk. However, no solid conclusion revealed the potential predictive value of mtDNA copy number for cancer prognosis. The present meta-analysis was performed to clarify the problem. Hence, we performed a systematic search in PubMed, EmBase, Web of Science databases independently and a total of eighteen studies comprising 3961 cases satisfied the criteria and finally enrolled. Our results didn’t show the association between them but significant heterogeneity in overall analysis (OS: HR = 0.923, 95% CI: 0.653–1.306, p = 0.652; DFS: HR = 0.997, 95% CI: 0.599–1.659, p = 0.99). However, subgroup analysis stratified by sample came to the opposite conclusion. High level mitochondrial DNA copy number in peripheral blood predicted a poor cancer prognosis (OS: HR = 1.624, 95% CI: 1.211–2.177, p = 0.001; DFS: HR = 1.582, 95% CI: 1.026–2.439, p = 0.038) while patients with high level mitochondrial DNA copy number in tumor tissue exhibited better outcomes (OS: HR = 0.604 95% CI: 0.406–0.899, p = 0.013; DFS: HR = 0.593, 95% CI: 0.411–0.857, p = 0.005). These findings were further proved in detailed analyses in blood or tissue subgroup. In conclusion, our study suggested the elevated mtDNA copy number in peripheral blood predicted a poor cancer prognosis while the better outcome was presented among patients with elevated mtDNA copy number in tumor tissue.

Altered mitochondrial DNA copy number contributes to human cancer risk: evidence from an updated meta-analysis

Accumulating epidemiological evidence indicates that the quantitative changes in human mitochondrial DNA (mtDNA) copy number could affect the genetic susceptibility of malignancies in a tumor-specific manner, but the results are still elusive. To provide a more precise estimation on the association between mtDNA copy number and risk of diverse malignancies, a meta-analysis was conducted by calculating the pooled odds ratios (OR) and the 95% confidence intervals (95% CI). A total of 36 case-control studies involving 11,847 cases and 15,438 controls were finally included in the meta-analysis. Overall analysis of all studies suggested no significant association between mtDNA content and cancer risk (OR = 1.044, 95% CI = 0.866–1.260, P = 0.651). Subgroup analyses by cancer types showed an obvious positive association between mtDNA content and lymphoma and breast cancer (OR = 1.645, 95% CI = 1.117–2.421, P = 0.012; OR = 1.721, 95% CI = 1.130–2.622, P = 0.011, respectively), and a negative association for hepatic carcinoma. Stratified analyses by other confounding factors also found increased cancer risk in people with drinking addiction. Further analysis using studies of quartiles found that populations with the highest mtDNA content may be under more obvious risk of melanoma and that Western populations were more susceptible than Asians.