Mitochondrial DNA ancestry, HPV infection and the risk of cervical cancer in a multiethnic population of northeastern Argentina

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.

Evolutionary analysis of JC polyomavirus in Misiones' population yields insight into the population dynamics of the early human dispersal in the Americas

BACKGROUND

JC polyomavirus (JCV) has an ethno-geographical distribution across human populations.

OBJECTIVE

Study the origins of the population of Misiones (Argentina) by using JCV as genetic marker.

METHODS

Viral detection and characterization was conducted by PCR amplification and evolutionary analysis of the intergenic region sequences.

RESULTS

22 out of 121 samples were positive for JCV, including 5 viral lineages: MY (n = 8), Eu-a (n = 7), B1-c (n = 4), B1-b (n = 2) and Af2 (n = 1). MY sequences clustered within a branch of Native American origin that diverged from its Asian counterpart about 21,914 years ago (HPD 95% interval 15,383-30,177), followed by a sustained demographic expansion around 5000 years ago.

CONCLUSIONS

JCV in Misiones reflects the multiethnic origin of the current population, with an important Amerindian contribution. Analysis of the MY viral lineage shows a pattern consistent with the arrival of early human migrations to the Americas and a population expansion by the pre-Columbian native societies.

Genetic variation in the E6 and E7 genes of human papillomavirus type 16 in northeastern Argentina

The province of Misiones is considered a region with a high mortality rate due to cervical cancer (CC). To gain insight into this problem, we explored the association between genetic variation in the E6 and E7 oncogenes of HPV16 and the risk of CC. We studied 160 women with cytological diagnoses of negative for intraepithelial lesion or malignity, low-grade squamous intraepithelial lesion, and high-grade squamous intraepithelial lesion/CC and a positive test for HPV16 infection. The genetic characterization of E6 and E7 genes was undertaken through PCR amplification and direct Sanger sequencing. Phylogenetic classification was conducted using Bayesian methods. To estimate the odds ratio (OR) for an association between genetic variants in the E6 and E7 genes and the risk of CC, we used ordinal logistic regression adjusted by age. The final data set comprised 112 samples. Diagnostic single-nucleotide polymorphisms (SNPs) and phylogenetic trees confirmed the presence of Lineage A (95.5%) and D (4.5%) in the samples. For the E6 gene, we identified eleven different sequences, with the most common ones being Lineage A E6 350G (58.9%) and E6 350T (37.5%). The E6 350G was associated with progression to HSIL/CC, with an OR of 19.41 (4.95-76.10). The E7 gene was more conserved than E6, probably due to the functional constraints of this small protein. Our results confirmed the association of the E6 350G SNP with a higher risk of developing CC. These data will contribute to understanding the biological bases of CC incidence in this region.

The correlation between high-risk HPV infection and precancerous lesions and cervical cancer

OBJECTIVE

To analyze the correlation between high-risk human papillomavirus (HPV) infection and precancerous lesions and cervical cancer.

METHODS

Patients with cervicitis (N=100), cervical intraepithelial neoplasia grade I (CIN I) (N=100), cervical intraepithelial neoplasia grades II-III (CIN II-III) (N=100) and cervical cancer (N=100) were enrolled. The exfoliated cervical cells were collected with the same method, and the detection of the HPV types was carried out by PCR-reverse dot blot (RDB) assay.

RESULTS

The top 5 HPV types in stage I-II cervical cancer were 16, 18, 52, 58, and 53, with a HPV positivity rate of 83.61%, while top 5 HPV types in stage III-IV cervical cancer were 16, 18, 58, 52, and 33, with a HPV positivity rate of 82.05%. The rate of high-risk HPV positivity for cervicitis was 5%, with HPV types of 16, 18, 52, and 33, 12% for CIN I, with HPV types of 16, 58, 52, 33, 56, 66, and 68, and 42% for CIN II-III, with HPV types of 16, 18, 58, 52, 33, 66, and 68. The prevalence of single, dual, and multiple HPV infection was 8.00%, 1.00%, and 0.00% for CIN I, 24.00%, 7.00%, and 1.00% for CIN II-III, and 57.00%, 25.00%, and 3.00% for cervical cancer, respectively. The age of patients with CIN I was mainly ≤24 and 25-34 years while CIN II-III in 25-34 and 35-44 years, and cervical cancer in 35-44 and 45-54 years.

CONCLUSION

The distribution of HPV subtypes in cervical cancer is closely related to the pathological types, lesion grades, and stages of cervical cancer. The incidence of cervical lesions varies with age, suggesting that high-risk groups should be well monitored and receive regular screening and timely HPV vaccination to effectively prevent cervical cancer.

Mitochondrial genetic variation in human bioenergetics, adaptation, and adult disease

OBJECTIVES

Mitochondria are critical for the survival of eukaryotic organisms due to their ability to produce cellular energy, which drives virtually all aspects of host biology. However, the effects of mitochondrial DNA (mtDNA) variation in relation to disease etiology and adaptation within contemporary global human populations remains incompletely understood.

METHODS

To develop a more holistic understanding of the role of mtDNA diversity in human adaptation, health, and disease, we investigated mitochondrial biology and bioenergetics. More specifically, we synthesized details from studies of mitochondrial function and variation in the context of haplogroup background, climatic adaptation, and oxidative disease.

RESULTS

The majority of studies show that mtDNA variation arose during modern human dispersal around the world. Some of these variants appear to have been positively selected for their adaptiveness in colder climates, with these sequence changes having implications for tissue-specific function and thermogenic capacity. In addition, many variants modulating energy production are also associated with damaging metabolic byproducts and mitochondrial dysfunction, which, in turn, are implicated in the onset and severity of several different adult mitochondrial diseases. Thus, mtDNA variation that governs bioenergetics, metabolism, and thermoregulation may potentially have adverse consequences for human health, depending on the genetic background and context in which it occurs.

CONCLUSIONS

Our review suggests that the mitochondrial research field would benefit from independently replicating mtDNA haplogroup-phenotype associations across global populations, incorporating potentially confounding environmental, demographic, and disease covariates into studies of mtDNA variation, and extending association-based studies to include analyses of complete mitogenomes and assays of mitochondrial function.

Maternal ancestry and hematological cancer risk: case-control study in an Argentinean population

Aim: We investigated the role of maternal ancestry in neoplastic hematological malignancies (HMs) risk in a population from Central Argentina. Materials & methods: We analyzed 125 cases with HMs and 310 controls from a public hospital, and a set of 202 colorectal, breast, lung, and hematologic cancer patients from a private hospital. Results: A decreased risk for HMs was associated with the Native American haplogroup B2 (odds ratio = 0.49; 95% CI: 0.25-0.92; p = 0.02). The sub-Saharan African parahaplogroup L was associated with higher susceptibility for disease (odds ratio = 3.10; 95% CI: 1.04-9.31; p = 0.043). Although the mean ancestral proportions in the total studied population was as published (61.7% Native American, 34.6% European and 3.7% African), an unequal distribution was observed between hospitals. Conclusion: We confirmed the tri-hybrid nature of the Argentinean population, with proportions varying within the country. Our finding supports the notion that associated haplogroup is population and cancer specific.

Genetic diversity of the JC polyomavirus (JCPyV) and mitochondrial DNA ancestry in Misiones, Argentina

BACKGROUND

The use of human and viral genetic markers offers a novel way to study human migration in multiethnic populations of Latin America.

OBJECTIVES

Our goal was to characterize the genetic diversity and geographical origins of JC Polyomavirus (JCPyV) and the genetic ancestry of mitochondrial DNA (mtDNA) in inhabitants from 25 de Mayo, Misiones-Argentina, a small village of largely German ancestry located close to the border with Brazil. We also evaluated the extent of agreement between viral and mtDNA markers for the different ancestry components of this population.

STUDY DESIGN

68 individuals were analyzed for JCPyV and mtDNA diversity. JCPyV detection and typing was conducted in urine samples by PCR amplification, sequencing and phylogenetic analysis of the VP1 gene. mtDNA ancestry was assessed through HVS1 sequencing, with the resulting haplotypes being classified into haplogroups of Amerindian, European and African origin. The distribution of JCPyV diversity and mtDNA ancestry in the population was statistically evaluated by Fisher exact test and the level of agreement of both markers at the individual level was evaluated by Cohen's kappa coefficient.

RESULTS

Our analysis showed that 57.4% of the samples were positive for JCPyV. Of these, the 47.6% were Asian-American Type 2, 33.3% European Type 1 and 19.1% African Type 3 in origin. The mtDNA ancestry of the study participants was 33.3% Amerindian and 66.7% European. There was a significant difference among the distribution of JCPyV diversity and mtDNA ancestry (p = 0.009) and at the individual level there was no correlation between the distribution of the both markers (κ = 0.154, p = 0.297).

CONCLUSION

The apparent incongruence between JCPyV diversity and mtDNA ancestry may reflect the original settlement process and more recent migration to 25 de Mayo, the latter involving viral spread through migrants from Brazil. Some potential limitations to our interpretations are also discussed.

The burden of 14 hr-HPV genotypes in women attending routine cervical cancer screening in 20 states of Mexico: a cross-sectional study

In Mexico, HPV vaccines available immunize against genotypes 16/18 and 16/18/6/11; however, there is limited surveillance about carcinogenic subtypes in different states of the country that allow evaluating the effectiveness of vaccination and cervical cancer screening programs. Here, we report the regional and age-specific prevalence of 14 hr-HPV genotypes as well as their prevalence in abnormal cytology (from ASCUS to cervical cancer) among Mexican women which were undergoing from cervical cancer screening in the Salud Digna clinics in 20 states of the country. This study includes women with social security from the majority of public health institutions (IMSS, ISSSTE, SEMAR, and PEMEX), and women without social security. For cervical cancer screening, we used the SurePath liquid-based cytology and the BD Onclarity HPV Assay. From December 1, 2016, to August 2, 2018, the hr-HPV prevalence among 60,135 women was 24.78%, the most prevalent types were HPV 16 (4.13%), HPV 31 (4.12%) and HPV 51 (3.39%), while HPV 18 (1.70%) was less prevalent among infected women. Interestingly, the genotypes not covered by current vaccines in Mexico were commonly found in precancerous lesions, evidencing their carcinogenic potential, so it is necessary to increase their surveillance and inclusion in cervical cancer screening triage.