Intakes of Vitamin A, C, and E, and β-Carotene Are Associated With Risk of Cervical Cancer: A Case-Control Study in Korea

Emerging paradigms: unmasking the role of oxidative stress in HPV-induced carcinogenesis

The contribution of the human papillomavirus (HPV) to cancer is significant but not exclusive, as carcinogenesis involves complex mechanisms, notably oxidative stress. Oxidative stress and HPV can independently cause genome instability and DNA damage, contributing to tumorigenesis. Oxidative stress-induced DNA damage, especially double-strand breaks, aids in the integration of HPV into the host genome and promotes the overexpression of two viral proteins, E6 and E7. Lifestyle factors, including diet, smoking, alcohol, and psychological stress, along with genetic and epigenetic modifications, and viral oncoproteins may influence oxidative stress, impacting the progression of HPV-related cancers. This review highlights various mechanisms in oxidative-induced HPV-mediated carcinogenesis, including altered mitochondrial morphology and function leading to elevated ROS levels, modulation of antioxidant enzymes like Superoxide Dismutase (SOD), Glutathione (GSH), and Glutathione Peroxidase (GPx), induction of chronic inflammatory environments, and activation of specific cell signaling pathways like the Phosphoinositide 3-kinase, Protein kinase B, Mammalian target of rapamycin (PI3K/AKT/mTOR) and the Extracellular signal-regulated kinase (ERK) signaling pathway. The study highlights the significance of comprehending and controlling oxidative stress in preventing and treating cancer. We suggested that incorporating dietary antioxidants and targeting cancer cells through mechanisms involving ROS could be potential interventions to mitigate the impact of oxidative stress on HPV-related malignancies.

Exploring the correlation between progression of human papillomavirus infection towards carcinogenesis and nutrition

Human papillomavirus (HPV) is a common sexually transmitted virus that can lead to the development of various types of cancer. While there are vaccines available to prevent HPV infection, there is also growing interest in the role of nutrition in reducing the risk of HPV-related cancers in HPV positive patients. Diet and nutrition play a critical role in maintaining overall health and preventing various diseases. A healthy diet can strengthen the immune system, which is essential for fighting off infections, including HPV infections, and preventing the growth and spread of cancer cells. Therefore, following a healthy diet and maintaining a healthy weight are important components of HPV and cancer prevention. This article explores the current scientific evidence on the relationship between nutrition and HPV, including the impact of specific nutrients, dietary patterns, and supplements on HPV infection toward cancer progression.

The Role of Micronutrients in Human Papillomavirus Infection, Cervical Dysplasia, and Neoplasm

There is evidence that diet and nutrition are modifiable risk factors for several cancers. In recent years, attention paid to micronutrients in gynecology has increased, especially regarding Human papillomavirus (HPV) infection. We performed a review of the literature up until December 2022, aiming to clarify the effects of micronutrients, minerals, and vitamins on the history of HPV infection and the development of cervical cancer. We included studies having as their primary objective the evaluation of dietary supplements, in particular calcium; zinc; iron; selenium; carotenoids; and vitamins A, B12, C, D, E, and K. Different oligo-elements and micronutrients demonstrated a potential protective role against cervical cancer by intervening in different stages of the natural history of HPV infection, development of cervical dysplasia, and invasive disease. Healthcare providers should be aware of and incorporate the literature evidence in counseling, although the low quality of evidence provided by available studies recommends further well-designed investigations to give clear indications for clinical practice.

The Preventive Role of the Vitamin D Endocrine System in Cervical Cancer

Vitamin D along with its active metabolite calcitriol and its metabolic and signaling system, known as the vitamin D endocrine system, have been widely recognized as a pivotal regulator of calcium homeostasis in addition to non-calcemic antitumoral effects in a variety of human cancers, including cervical cancer. Several studies have found an inverse relationship between the incidence of cervical neoplasia and vitamin D levels. This narrative review updates the current evidence supporting the notion that the vitamin D endocrine system has a preventive role on cervical cancer, mainly in the early phases of the disease, acting at the level of suppressing cell proliferation, promoting apoptosis, modulating inflammatory responses, and probably favoring the clearance of human papillomavirus-dependent cervical lesions. Although an optimal vitamin D status helps in the prevention and regression of low-grade squamous intraepithelial lesions of the cervix, it appears that vitamin D alone or combined with chemotherapeutic agents has little effectivity once advanced cervical cancer is established. These observations suggest that an optimal vitamin D status might exert beneficial actions in the early phases of cervical cancer by preventing its onset and progression.

Non-Genetic Factors and Risk of Cervical Cancer: An Umbrella Review of Systematic Reviews and Meta-Analyses of Observational Studies

Objectives: The association between non-genetic risk factors and cervical cancer (CC) remains controversial and unclear. This umbrella review was conducted to evaluate and synthesize previously published systematic reviews and meta-analyses related to non-genetic factors and CC risk.

Methods: We searched PubMed, Web of Science, and EMBASE to identify studies investigating the association between extragenetic factors and CC risk. For each article, we calculated the summary effect size and the 95% confidence interval. Specific criteria were used to classify the association into four levels: strong, highly suggestive, suggestive, or weak.

Results: A total of 18 meta-analyses of different risk factors for CC were examined; these studies covered risk factors related to diet, lifestyle, reproduction, disease, viral infection, microorganisms, and parasites. Oral contraceptive use and Chlamydia trachomatis infection were shown to increase CC risk, and this was supported by strong evidence. Additionally, there were four risk factors supported by highly suggestive evidence and six risk factors supported by suggestive evidence.

Conclusion: In conclusion, there is a strong association between oral contraceptive use, Chlamydia trachomatis infection, and increased CC risk.

Dietary Vitamin A Intake and Circulating Vitamin A Concentrations and the Risk of Three Common Cancers in Women: A Meta-Analysis

BACKGROUND

According to relevant clinical research, dietary and circulating antioxidants vitamin A are connected with the risk of breast, cervical, and ovarian cancer in women. However, there was inconsistency between the findings. We completed this meta-analysis at the right moment to address this contradiction of the problem.

METHODS

Web of Science, Embase, and PubMed databases were searched using the proposed search strategy and filtered using the inclusion and exclusion criteria as well as the NOS quality score. As of May 2022, low intake or low concentration was used as a control, and odds ratio (OR) or relative risk (RR) and ninety-five percent confidence intervals (95% CI) were extracted for high intake. Stata 12.0 was used to process the data.

RESULTS

Our meta-analysis included a total of 49 studies, 29 on breast cancer, 10 on ovarian cancer, and 10 on cervical cancer. There were 38 case-control studies included, with 25,363 cases and 42,281 controls; there were 11 cohort studies included, 1,334,176 individuals were followed up, and finally 9496 obtained cancer. The pooled OR value results were as follows: diet or supplements (OR = 0.83, 95% CI 0.76-0.90, I ² = 56.1%) and serum or plasma (OR = 0.96, 95% CI 0.86-1.09, I ² = 29.5%). Subgroup analyses were performed according to cancer type, diet or supplements, serum or plasma, study type, and geographic regions.

CONCLUSIONS

In North American and Asian populations, high dietary consumption of vitamin A or supplements decreases the incidence of three cancers in women, with breast and ovarian cancers being more significant. However, high circulating vitamin A concentrations were not significantly connected with the risk of the three malignancies.

Antioxidant and inflammatory potential of diet among women at risk of cervical cancer: findings from a cross-sectional study in Italy

OBJECTIVE

To evaluate the association of Composite Dietary Antioxidant Index (CDAI) and Dietary Inflammatory Index (DII) with the prevalence of high-grade cervical intraepithelial neoplasia (CIN).

DESIGN

A cross-sectional study was conducted on women with abnormal Papanicolaou test, who underwent high-risk human papillomavirus (HPV) screening and histological test through colposcopy. Dietary data were collected using a FFQ and used to assess both CDAI and DII.

SETTING

Women were recruited from 2012 to 2015 at the Cervical Cancer Screening Unit of the 'Azienda Sanitaria Provinciale' of Catania (Italy).

PARTICIPANTS

The study included 539 women with a mean age of 40·2 years, who were classified as cases (n 127 with CIN2 or more severe lesions) and controls (n 412 with normal cervical epithelium or CIN1).

RESULTS

Although we observed a lower proportion of HPV-positive women among those with higher CDAI (P < 0·001), the index was not associated with the diagnosis of CIN2 or more severe lesions. By contrast, women with medium or high DII showed higher odds to be diagnosed with CIN2 or more severe lesions than those with low DII (OR = 2·15; 95 % CI 1·11, 4·17; P = 0·024 and OR = 3·14; 95 % CI 1·50, 6·56; P = 0·002, respectively), after adjusting for age, HPV status, educational level, BMI, smoking status, parity, use of oral contraceptives and supplements.

CONCLUSIONS

Our findings suggested that a pro-inflammatory diet might be associated with an increased risk of CIN2 and more severe lesions. However, further prospective studies should be encouraged to support this evidence.

Role of Vitamin C in Selected Malignant Neoplasms in Women

Since the first reports describing the anti-cancer properties of vitamin C published several decades ago, its actual effectiveness in fighting cancer has been under investigation and widely discussed. Some scientific reports indicate that vitamin C in high concentrations can contribute to effective and selective destruction of cancer cells. Furthermore, preclinical and clinical studies have shown that relatively high doses of vitamin C administered intravenously in ‘pharmacological concentrations’ may not only be well-tolerated, but significantly improve patients’ quality of life. This seems to be particularly important, especially for terminal cancer patients. However, the relatively high frequency of vitamin C use by cancer patients means that the potential clinical benefits may not be obvious. For this reason, in this review article, we focus on the articles published mainly in the last two decades, describing possible beneficial effects of vitamin C in preventing and treating selected malignant neoplasms in women, including breast, cervical, endometrial, and ovarian cancer. According to the reviewed studies, vitamin C use may contribute to an improvement of the overall quality of life of patients, among others, by reducing chemotherapy-related side effects. Nevertheless, new clinical trials are needed to collect stronger evidence of the role of this nutrient in supportive cancer treatment.

Antioxidants Associated With Oncogenic Human Papillomavirus Infection in Women

BACKGROUND

Human papillomavirus (HPV) infection is a major cause of cervical cancer. Studies showed the onset of HPV carcinogenesis may be induced by oxidative stress affecting the host immune system. The association between antioxidants and oncogenic HPV remains unclear. In this study, we aim to identify antioxidants associated with vaginal HPV infection in women.

METHODS

The associations between the 15 antioxidants and vaginal HPV infection status (no, low-risk [LR], and high-risk [HR] HPV) were evaluated using 11 070 women who participated in the 2003-2016 National Health and Nutrition Examination Survey (NHANES).

RESULTS

We identified serum albumin and 4 dietary antioxidants (vitamin A, B2, E, and folate) inversely associated with HR-HPV infection. Women with a low level of albumin (≤39 g/L) have a significantly higher risk of HR-HPV (odds ratio [OR] = 1.4, P = .009 vs >44 g/L). A Nutritional Antioxidant Score (NAS) was developed based on these 4 dietary antioxidants. The women with the lowest quartile NAS had a higher chance of HR-HPV (OR = 1.3, P = .030) and LR-HPV (OR = 1.4, P = .002) compared with the women with the highest quartile NAS.

CONCLUSIONS

We identified 5 antioxidants negatively associated with vaginal HR-HPV infection in women. Our findings provide valuable insights into understanding antioxidants' impact on HPV carcinogenesis.

Role of Vitamin E in Selected Malignant Neoplasms in Women

Vitamin E, which is actually a mixture of eight isoforms (four tocopherols and four tocotrienols), is a powerful antioxidant that protects polyunsaturated fatty acids against oxidation and has the ability to break the chain lipid peroxidation, which is used in the treatment of heart disease, atherosclerosis, muscle disorders or infertility among men. Studies in-vitro show that one of the effects of tocopherol is the reduction of cancer stem cell activity which is connected to poor clinical course. In the scientific literature, reports on the participation of vitamin E not only in protection against the mutagenic effects of reactive oxygen species, but also in its anti-angiogenic activity and the ability to inhibit the invasion and metastasis of neoplastic cells are increasingly common. In this context, the role of vitamin E in preventing the neoplastic process and selected malignant neoplasms among women seems to be of particular interest. In this article, we present the results of research on the potential anticancer effects of vitamin E in the fight against breast, cervical, endometrial and ovarian cancer.

In situ immunopathological events in human cervical intraepithelial neoplasia and cervical cancer: Review

Neoplasia of the cervix represents one of the most common cancers in women. Clinical and molecular research has identified immunological impairment in squamous intraepithelial cervical lesions and cervical cancer patients. The in-situ expression of several cytokines by uterine epithelial cells and by infiltrating leukocytes occurs during the cervical intraepithelial neoplasia and cervical cancer. Some of these cytokines can prevent and others can induce the progression of the neoplasm. The infiltrating leukocytes also produce cytokines and growth factors relate to angiogenesis, chemotaxis, and apoptosis capable of modulating the dysplasia progression. In this review we analyzed several interleukins with an inductive effect or blocking effect on the neoplastic progression. We also analyze the genetic polymorphism of some cytokines and their relationship with the risk of developing cervical neoplasia. In addition, we describe the leukocyte cells that infiltrate the cervical uterine tissue during the neoplasia and their effects on neoplasia progression.

Association of Diet Quality and Dietary Components with Clinical Resolution of HPV

Nutrient deficits have been repeatedly linked to cervical human papillomavirus (HPV) persistence, cervical neoplasia, and cervical cancer in case-control studies. This study sought to examine the relationship between overall diet quality and dietary components with the spontaneous resolution of cervical HPV over one year. A prospective observational cohort study was performed. Women with low-grade cervical cytology and/or positive HPV test completed a 24-hour dietary recall, from which the Healthy Eating Index (HEI)-2010, a score of overall diet quality, and scores in dietary categories were calculated. Participants were managed clinically according to national management guidelines. Those whose subsequent testing demonstrated normalization of cytology and/or HPV testing ("HPV resolution") were compared to those whose abnormalities persisted or progressed ("HPV non-resolution"). Twenty-six women were included in the HPV resolution group and 38 in the non-resolution group. They were observed for a median of 428 and 412 day, respectively (p = 0.09). There was no difference in overall diet quality between the groups. Intake of total and whole fruit, and seafood/plant protein were associated with HPV resolution in a logistic regression model (all p < 0.05). These findings could have important implications for the counseling and management of individuals with HPV infection of the cervix.

Dietary Antioxidant Intake and Human Papillomavirus Infection: Evidence from a Cross-Sectional Study in Italy

Several lines of evidence suggested that antioxidants might play a protective role against high-risk human papillomavirus (hrHPV) infection and cervical cancer. However, the effect of combined intake of antioxidants has not been investigated thus far. The current cross-sectional study aimed to understand the relationship between dietary antioxidant intake and the risk of high-risk HPV (hrHPV) infection among 251 Italian women with normal cervical cytology. Women were tested for hrHPV using the Digene HC2 HPV DNA Test. Dietary antioxidant intakes were assessed using a semi-quantitative food frequency questionnaire, and a Composite Dietary Antioxidant Index (CDAI) was constructed on the basis of zinc, selenium, manganese, vitamin A, vitamin C, vitamin E, carotenoid, and flavonoid intake. Logistic regression analysis was used to assess odds ratio (OR) and 95% confidence interval (95% CI) for the associations of antioxidant intakes or CDAI with hrHPV status, adjusting for age, smoking status, body mass index, parity, educational level, marital status, and use of multivitamins and oral contraceptives. We first observed that hrHPV-positive women (n = 84) reported lower intake of zinc, manganese, and vitamins A and C than non-infected women. Specifically, we found a negative association between dietary intake of zinc and hrHPV-positive status when all antioxidants were considered simultaneously (OR = 0.46; 95% CI = 0.27–0.80; p = 0.006). With respect to cumulative dietary antioxidant intake, we demonstrated that women with high CDAI (third tertile) had lower odds of being hrHPV-positive than those with low CDAI (first tertile) (OR = 0.39; 95% CI = 0.18–0.85; p = 0.018). To our knowledge, this is the first study demonstrating that a diet based on the combined intake of nutrients with antioxidant properties might reduce the risk of hrHPV infection. However, further research is needed to understand whether dietary antioxidant intake is associated with hrHPV infection or its persistence.

Dietary carotenoids in cancer chemoprevention and chemotherapy: A review of emerging evidence

In recent years, natural products have reemerged as biotherapeutic options, with several dietary carotenoids, viz. astaxanthin, fucoxanthin, siphonaxanthin, β-cryptoxanthin, α-carotene, β-carotene, and lycopene, developing as potential candidates for chemoprevention and chemotherapeutics of breast, colorectal, lung, and prostate cancers. The potent cytotoxic and antiproliferative effects of carotenoids against various cancer cells are mediated by a wide range of molecular mechanisms modulating oxidative stress and redox balance, mitogen-activated protein kinases (MAPK) and other cellular signaling proteins, transcription factors, caspase cascade pathways of apoptosis, cell cycle progression and proliferation, angiogenesis, metastasis, gap junction intercellular communication (GJIC), and multidrug resistance (MDR). This review discusses recent evidence demonstrating the crucial roles of carotenoids in these cellular and molecular events of cancer cell cytotoxicity. In addition, recent case-control and cohort studies are discussed to support the potential role of carotenoids in cancer prevention and therapy.

CGSEA: A Flexible Tool for Evaluating the Associations of Chemicals with Complex Diseases

The etiology of many human complex diseases or traits involves interactions between chemicals and genes that regulate important physiological processes. It has been well documented that chemicals can contribute to disease development through affecting gene expression in vivo. In this study, we developed a flexible tool CGSEA for scanning the candidate chemicals associated with complex diseases or traits. CGSEA only need genome-wide summary level data, such as transcriptome-wide association studies (TWAS) and mRNA expression profiles. CGSEA was applied to the GWAS summaries of attention deficiency/hyperactive disorder, (ADHD), autism spectrum disorder (ASD) and cervical cancer. CGSEA identified several significant chemicals, which have been demonstrated to be involved in the development or treatment of ADHD, ASD and cervical cancer. The CGSEA program and user manual are available at https://github.com/ChengSQXJTU/CGSEA.

New Insights in the Pathogenesis of HPV Infection and the Associated Carcinogenic Processes: The Role of Chronic Inflammation and Oxidative Stress

Human papillomavirus (HPV) is a small double-stranded DNA virus with tropism for epithelial cells. To this date, over 150 genotypes are known and are classified into two major groups, low-risk and high-risk strains, depending on the ability of the virus to induce malignant transformation. The host's immunity plays a central role in the course of the infection; therefore, it may not be clinically manifest or may produce various benign or malignant lesions. The pathogenic mechanisms are complex and incompletely elucidated. Recent research suggests the role of chronic inflammation and oxidative stress (OS) in the pathogenesis of HPV infection and the associated carcinogenic processes. Chronic inflammation induces OS, which in turn promotes the perpetuation of the inflammatory process resulting in the release of numerous molecules which cause cell damage. Reactive oxygen species exert a harmful effect on proteins, lipids, and nucleic acids. Viral oncogenes E5, E6, and E7 are involved in the development of chronic inflammation through various mechanisms. In addition, HPV may interfere with redox homeostasis of host cells, inducing OS which may be involved in the persistence of the infection and play a certain role in viral integration and promotion of carcinogenesis. Knowledge regarding the interplay between chronic inflammation and OS in the pathogenesis of HPV infection and HPV-induced carcinogenesis has important consequences on the development of new therapeutic strategies.

The Association of Dietary Patterns with High-Risk Human Papillomavirus Infection and Cervical Cancer: A Cross-Sectional Study in Italy

Specific foods and nutrients help prevent the progression of persistent high-risk human papillomavirus (hrHPV) infection to cervical cancer (CC). The aim of this study was to investigate dietary patterns which may be associated with hrHPV status and the risk of high-grade cervical intraepithelial neoplasia (CIN2+). Overall, 539 eligible women, including 127 with CIN2+, were enrolled in a cross-sectional study, and tested for hrHPV infection. Food intake was estimated using a food frequency questionnaire. Logistic regression models were applied. Using the Mediterranean Diet Score, we demonstrated that, among 252 women with a normal cervical epithelium, medium adherence to the Mediterranean diet decreased the odds of hrHPV infection when compared to low adherence (adjOR = 0.40, 95%CI = 0.22-0.73). Using the principal component analysis, we also identified two dietary patterns which explained 14.31% of the variance in food groups intake. Women in the third and fourth quartiles of the "Western pattern" had higher odds of hrHPV infection when compared with first quartile (adjOR = 1.77, 95% CI = 1.04-3.54 and adjOR = 1.97, 95%CI = 1.14-4.18, respectively). Adjusting for hrHPV status and age, women in the third quartile of the "prudent pattern" had lower odds of CIN2+ when compared with those in the first quartile (OR = 0.50, 95%CI = 0.26-0.98). Our study is the first to demonstrate the association of dietary patterns with hrHPV infection and CC and discourages unhealthy habits in favour of a Mediterranean-like diet.

Effect of vitamin E supplementation on uterine cervical neoplasm: A meta-analysis of case-control studies

Several epidemiological studies have suggested that vitamin E could reduce the risk of uterine cervical neoplasm. However, controversial data were presented by different reports. Hence, we conducted a meta-analysis to assess the relationship between vitamin E and the risk of cervical neoplasia. We performed a comprehensive search of the PubMed, Embase and Cochrane databases through December 31, 2016. Based on a fixed-effects or random-effects model, the odds ratio (OR) and 95% confidence intervals (CIs) were calculated to assess the combined risk. Subgroup analyses and meta-regression were done to assess the source of heterogeneity. Subgroup analyses were performed according to survey ways, types of cervical neoplasia, study populations. A protocol was registered with PROSPERO (No. CRD42016036672). In total, 15 case-control studies were included, involving 3741 cases and 6328 controls. Our study suggested that higher category of vitamin E could reduce the cervical neoplasia risk (OR = 0.58, 95% CIs = 0.47–0.72, I² = 83%). In subgroup-analysis, both vitamin E intake and blood levels of vitamin E had a significant inverse association with the risk of cervical neoplasm. Additionally, we found the same relationship between vitamin E and cervical neoplasia among different populations and types of cervical neoplasia. Meta-regression showed that none of the including covariates were significantly related to the outcomes. No evidence of publication bias was observed. In conclusion, vitamin E intake and blood vitamin E levels were inversely associated with the risk of cervical neoplasia.

Association between folate status and cervical intraepithelial neoplasia

Background/Objectives:

To investigate the effect of folate status on cervical intraepithelial neoplasia (CIN) progression and its relationship with high-risk human papillomavirus (hrHPV).

Subjects/Methods:

We evaluated 20 000 sexually active women aged <65 years in Yangqu County by using a questionnaire; the subjects were also screened using the ThinPrep cytologic test (TCT). Patients with abnormal TCT results (other than glandular cell abnormalities) who were willing to provide informed consent were further diagnosed using colposcopy and histopathological examination. We investigated 247 cases of low-grade cervical squamous intraepithelial lesions (LSIL), 125 cases of high-grade cervical squamous intraepithelial lesions (HSIL) and 877 controls. A 24-item food frequency questionnaire was filled out by the investigator to estimate the consumption of dietary folate. Positivity for hrHPV from residual exfoliated cervical cells was tested; serum folate was also measured.

Results:

The hrHPV infection rate in HSIL patients (77.6%) was higher than that in LSIL (33.2%) and control (32.0%) patients. Dietary folate intakes in controls, LSIL and HSIL were 306.9±176.6, 321.8±168.0 and 314.7±193.8 μg/kcal, respectively. The levels of serum folate in controls, LSIL and HSIL were 18.2±7.9, 15.9±7.1 and 14.3±7.5 nmol/l, respectively. Increased CIN correlated with higher rates of hrHPV infection and lower levels of serum folate.

Conclusions:

Low levels of serum folate may increase the risk of CIN progression. Furthermore, potential synergy may exist between low serum folate levels and hrHPV infection to promote CIN development.

Association between vitamin C Intake and the risk of cervical neoplasia: A meta-analysis

To assess the association between vitamin C intake and cervical neoplasia (CN) risk. Databases including PubMed, Embase, and Springer link were retrieved up to June 10, 2014 with predefined strategy. The combined odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated for overall and subgroup analyses. The publication bias was assessed using Begg's test and Egger's test. Sensitivity analysis was also conducted. Twelve studies consisting of 1 prospective cohort study and 11 case-control studies were included. In overall analysis, vitamin C intake was significantly associated with the reduced risk of CN (OR = 0.58; 95% CI: 0.44 to 0.75; P < 0.001). Subgroup analysis stratified by vitamin C dose indicated all dose categories achieved a reduced CN risk. Furthermore, increased vitamin C intake by 50 mg/day was related to the reduced risk of CN (OR = 0.92; 95% CI: 0.89 to 0.94; P < 0.05). No publication bias was detected by Begg's test (P = 0.169) and no apparent fluctuation was observed in summary OR by sensitivity analysis. Vitamin C intake was inversely associated with the risk of CN and this association was dose-dependent. However, more randomized controlled trials are required for further validation.

Vitamin C intake and risk of renal cell carcinoma: a meta-analysis

Studies have showed that vitamin C intake is linked to renal cell carcinoma risk, however, the results were inconsistent. Hence, the present meta-analysis was to examine the association between vitamin C intake and RCC risk. We searched the published studies that reported the relationship between vitamin C intake and RCC risk using PubMed and Embase up to January 2015. Based on a fixed effects model, RR and the corresponding 95% CI were used to assess the pooled risk. 3 prospective cohort studies and 7 case-control studies were included. The overall RR (95% CI) of RCC for the highest vs. the lowest levels of vitamin C intake was 0.78(0.69,0.87). Little evidence of heterogeneity was found. In the subgroup analyses, we found an inverse association between vitamin C intake and RCC risk in the case-control studies but not in the prospective cohort studies. Additionally, this association between vitamin C intake and RCC risk was not differed by population distribution. Our study provides evidence that vitamin C intake is associated with a reduced RCC risk. However, our conclusion was just based on ten including studies, so more high-quality of case-control studies or cohort studies which report this topic are needed.

Biochemical changes associated with ascorbic acid-cisplatin combination therapeutic efficacy and protective effect on cisplatin-induced toxicity in tumor-bearing mice

Cisplatin is one of the well-established anticancer drugs being used against a wide spectrum of cancers. However, full therapeutic efficacy of the drug is limited due to development of various toxicities in the host. This study examines the comparative therapeutic effectiveness and toxicities of cisplatin alone and in combination of dietary ascorbic acid (AA) in ascites Dalton's lymphoma-bearing mice. The findings show that the combination treatment of mice with ascorbic acid plus cisplatin has much better therapeutic efficacy against murine ascites Dalton's lymphoma (DL) in comparison to cisplatin alone and this may involve a decrease in reduced glutathione (GSH), catalase activity and increased lipid peroxidation (LPO) in Dalton's lymphoma tumor cells. At the same time, combination treatment indicates a protective role of ascorbic acid against cisplatin-induced tissue toxicities (side effects) in the hosts. Cisplatin-induced histopathological changes in liver, kidney and testes were decreased after combination treatment. The analysis of renal function test (RFT), liver function test (LFT) and sperm abnormalities also suggest an improvement in these parameters after combination treatment. Therefore, it may be concluded that the increased GSH level, catalase activity and decreased LPO in the tissues, i.e., liver, kidney and testes after combination treatment may be involved in its protective ability against cisplatin-induced tissue toxicities in the host.

Vitamin E Intake and Risk of Renal Cell Carcinoma: A Meta-Analysis of 7 Case-Control Studies

OBJECTIVE

Vitamin E intake may reduce the risk of renal cell carcinoma, but the results were inconsistent. Hence, we conducted a meta-analysis to assess the association between dietary vitamin E intake and the risk of renal cell carcinoma.

METHODS

We searched PubMed to identify the relevant case-control studies up to June 2014. Reference lists of retrieved articles were also reviewed. Odds ratios and corresponding 95% confidence intervals were used to estimate the association between dietary vitamin E intake and the risk of renal cell carcinoma.

RESULTS

We identified 7 case-control studies regarding dietary vitamin E intake and risk of renal cell carcinoma, involving 5789 cases and 14866 controls. The odds ratio of renal cell carcinoma for the highest compared with the lowest dietary vitamin E intake was 0.75 (95% confidence interval: 0.59-0.91), and heterogeneity was observed across studies. The association between dietary vitamin E intake and the risk of renal cell carcinoma was not significantly differed by gender, but this association were inconsistent in the North American and European populations.

CONCLUSION

Our study provided a evidence that there was a significant inverse association of dietary vitamin E intake with risk of renal cell carcinoma. However, this finding was based on the case-control studies, more well-designed cohort studies are needed.

A review of dietary prevention of human papillomavirus-related infection of the cervix and cervical intraepithelial neoplasia

The natural history of cervical cancer suggests that prevention can be achieved by modification of the host's immune system through a nutrient-mediated program. This study reviews the preventive role of dietary intake on cervical intraepithelial neoplasia (CIN) induced by human papillomavirus (HPV). Electronic databases were searched using relevant keywords such as, but not limited to, human papillomavirus infection, cervical intraepithelial neoplasia, lifestyle factors, nutrients intake, and diet. High consumption of fruit and vegetables appears to be protective against CIN. The findings also highlight the possibility of consuming high levels of specific nutrients, vitamins, and minerals, and retaining sufficient level of these elements in the body, especially those with high antioxidants and antiviral properties, to prevent progression of transient and persistent HPV infections to high-grade CIN 2 and 3 (including in situ cervical cancer). The protective effect is not significant for high-risk HPV persistent infections and invasive cervical cancer. Although it appears that intake of specific nutrients, vitamins, and minerals may be good in CIN prevention, there is lack of evidence from controlled trial to confirm this. Health professionals shall focus on implementation of a balanced-diet prevention strategy at an early stage for cervical cancer prevention.

Case-control study of diet in patients with cervical cancer or precancerosis in Wufeng, a high incidence region in China

PURPOSE

To investigate the diet of patients with cervical cancer and precancerosis in the Wufeng area, a high- incidence region in China.

METHODS

In the case group, 104 patients diagnosed with cervical cancer or cervical intraepithelial neoplasias (CINII/III) were recruited from the Wufeng area. Nine hundred thirty-six healthy women were selected from the same area as the matched controls. A questionnaire, which included questions about general lifestyle conditions, smoking and alcohol status, source of drinking water, green tea intake, and diet in the past year, was presented to all participants.

RESULTS

Green tea intake (P=0.022, OR=0.551, 95% CI=0.330-0.919) and vegetable intake (P=0.035, OR=0.896, 95% CI=0.809-0.993) were identified as protective factors against cervical cancer or CINII/III. There was no indication of any associations of other lifestyle factors (smoking status, alcohol status, source of drinking water) or diet (intake of fruit, meat/egg/milk, soybean food, onion/garlic, staple food and pickled food) with cervical cancer.

CONCLUSIONS

The results suggest that eating more fresh vegetables and drinking more green tea may help to reduce the risk of cervical cancer or CINII/III in people of the Wufeng area.

Defective antioxidant systems in cervical cancer

Cervical cancer remains a great problem for woman health, as it is the second deadly cancer of females worldwide. The infection of human papilloma virus (HPV) is the major risk factor for this cancer, although several other factors are also associated. Oxidative stress or antioxidant deficiency has been frequently identified to be associated with cervical cancer. Defects in the antioxidant enzyme systems are reported to play important role behind this antioxidant deficiency, which is responsible for the production of reactive oxygen species and ultimately, DNA damage in cervical cells. In response, cells become more vulnerable to HPV infection for cervical cancer development. Recently, antioxidant therapies or dietary supplementation of antioxidants have gained considerable interests in the cervical cancer treatment. In this study, we have reviewed the association of defective antioxidant systems and cervical cancer development. The recent advances in both of the basic and clinical research focusing on possible antioxidant therapy have also been discussed.

Carotenoids and total phenolic contents in plant foods commonly consumed in Korea

Phytochemicals are reported to provide various biological functions leading to the promotion of health as well as the reduced risk of chronic diseases. Fat-soluble plant pigments, carotenoids, are extensively studied micronutrient phytochemicals for their potential health benefits. It is noteworthy that specific carotenoids may be responsible for different protective effects against certain diseases. In addition, each carotenoid can be obtained from different types of plant foods. Considering the fact that the phytochemical content in foods can vary according to, but not limited to, the varieties and culture conditions, it is important to establish a database of phytochemicals in locally produced plant foods. Currently, information on individual carotenoid content in plant foods commonly consumed in Korea is lacking. As the first step to support the production and consumption of sustainable local plant foods, carotenoids and total phenolic contents of plant foods commonly consumed in Korea are presented and their potential biological functions are discussed in this review.

Retinol induces morphological alterations and proliferative focus formation through free radical-mediated activation of multiple signaling pathways

AIM

Toxicity of retinol (vitamin A) has been previously associated with apoptosis and/or cell malignant transformation. Thus, we investigated the pathways involved in the induction of proliferation, deformation and proliferative focus formation by retinol in cultured Sertoli cells of rats.

METHODS

Sertoli cells were isolated from immature rats and cultured. The cells were subjected to a 24-h treatment with different concentrations of retinol. Parameters of oxidative stress and cytotoxicity were analyzed. The effects of the p38 inhibitor SB203580 (10 μmol/L), the JNK inhibitor SP600125 (10 μmol/L), the Akt inhibitor LY294002 (10 μmol/L), the ERK inhibitor U0126 (10 μmol/L) the pan-PKC inhibitor Gö6983 (10 μmol/L) and the PKA inhibitor H89 (1 μmol/L) on morphological and proliferative/transformation-associated modifications were studied.

RESULTS

Retinol (7 and 14 μmol/L) significantly increases the reactive species production in Sertoli cells. Inhibition of p38, JNK, ERK1/2, Akt, and PKA suppressed retinol-induced [(3)H]dT incorporation into the cells, while PKC inhibition had no effect. ERK1/2 and p38 inhibition also blocked retinol-induced proliferative focus formation in the cells, while Akt and JNK inhibition partially decreased focus formation. ERK1/2 and p38 inhibition hindered transformation-associated deformation in retinol-treated cells, while other treatments had no effect.

CONCLUSION

Our results suggest that activation of multiple kinases is responsible for morphological and proliferative changes associated to malignancy development in Sertoli cells by retinol at the concentrations higher than physiological level.

Vitamin A and risk of cervical cancer: a meta-analysis

OBJECTIVE

To conduct a systematic review with meta-analysis of studies assessing the association of vitamin A (retinol, carotene and other carotenoids) intake or blood (serum or plasma) levels of vitamin A (retinol and carotene) with risk of cervical cancer.

METHODS

We evaluated the studies published in English and Chinese on diet or blood vitamin A for the risk of cervical cancer. We also reviewed reference lists from retrieved articles. Meta-analysis was applied to calculate the combined effect values and their 95% confidence intervals. The risk of bias was assessed by the Egger regression asymmetry test.

RESULTS

As many as 11 articles on dietary vitamin A and 4 articles on blood vitamin A were selected according to the eligibility criteria and were included in the meta-analysis, for a total of 12,136 participants. The pooled odds ratios (ORs) of cervical cancer were 0.59 (95% CI, 0.49-0.72) for total vitamin A intake and 0.60 (95% CI, 0.41-0.89) for blood vitamin A levels. The combined ORs of cervical cancer were 0.80 (95% CI, 0.64-1.00), 0.51 (95% CI, 0.35-0.73) and 0.60 (95% CI, 0.43-0.84) for retinol, carotene and other carotenoid intake, and 1.14 (95% CI, 0.83-1.56) and 0.48 (95% CI, 0.30-0.77) for blood retinol and carotene.

CONCLUSIONS

Vitamin A intake and blood vitamin A levels were inversely associated with the risk of cervical cancer in this meta-analysis.

Selective suppression of cervical cancer Hela cells by 2-O-β-D-glucopyranosyl-L-ascorbic acid isolated from the fruit of Lycium barbarum L

Lycium barbarum fruit has been used as a Chinese traditional medicine and dietary supplement for centuries. 2-O-β-D-Glucopyranosyl-L-ascorbic acid (AA-2βG), a novel stable vitamin C analog, is one of the main biologically active components of the fruit. In this report, we investigated the cytotoxic and antiproliferative effect of AA-2βG against cancer cells in vitro and identified the proteins with significantly differential expression in the cervical cancer cells (Hela) cultured in the presence of AA-2βG proteomic analysis. Our results demonstrated that the cytotoxic and antiproliferative activity of AA-2βG on cancer cell lines were in a cell type-, time-, and dose-dependent manner. Similar to vitamin C, the AA-2βG selectively induced cell death repressed the proliferation of Hela cells by the mechanism of cell apoptosis and cell cycle arrest induced by AA-2βG through a mechanism of stabilizing p53 protein. However, the biological activity of inhibition of cell proliferation in other malignant cancer cell lines or primary cells were varied, as demonstrated by either moderate inhibition or slight promotion following treatment with AA-2βG. Comparative analysis of the proteomic profiles and immunoblot analysis identified 15 proteins associated with repressing cell apoptosis and/or stimulating cell proliferation in Hela cells that were downregulated in the presence of AA-2βG or vitamin C. These data indicate that a mechanism of the AA-2βG and vitamin C mediated antitumor activity by downregulating the expression of proteins involved in cell apoptosis and proliferation and consequently inducing Hela cell apoptosis and cell cycle arrest, suggesting that AA-2βG and vitamin C may share a similar mechanism of inducing Hela cell apoptosis. These results also suggest that the L. barbarum fruit may be a potential dietary supplement and anticancer agent aimed at the prevention and treatment of cervical cancer.