Human papillomavirus in esophageal squamous cell carcinoma of the high-risk Kazakh ethnic group in Xinjiang, China

HPV 16 E6 promotes growth and metastasis of esophageal squamous cell carcinoma cells in vitro

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies worldwide. Increasing evidence suggests that human papillomavirus (HPV) infection may be associated with the etiology of ESCC. However, the precise role of HPV in ESCC remains unclear.

METHODS AND RESULTS

Proliferation and apoptosis of ESCC cells upon infection with HPV16 E6 were detected using CCK-8 assays and Western blot analyses. The migration rate was measured with a wound healing assay, and a Transwell Matrigel invasion assay was used to detect the invasive ability. RT-qPCR was performed to detect the expression of E6AP, p53, and miR-34a. The proliferation rates were significantly higher in HPV16E6-transfected cell groups compared with the negative control groups. Bax protein expression was downregulated in HPV16E6-treated groups compared to the controls. The wound healing and Transwell Matrigel invasion assays indicated that HPV16 E6 infection could increase ESCC cell migration and invasion. Furthermore, E6AP, p53 and miR-34a expression were decreased in HPV16 E6-transfected cell lines.

CONCLUSION

Our results not only provide evidence that HPV16 E6 promotes cell proliferation, migration, and invasion in ESCC, but also suggests a correlation between HPV infection and E6AP, p53 and miR-34a expression. Consequently, HPV16 E6 may play an important role in ESCC development.

Incidence and risk factors of second primary cancer after the initial primary human papillomavirus related neoplasms

Comprehensive studies in second primary cancer (SPC) after the initial primary human papillomavirus (HPV)-related cancer still remain warranted. We aimed to analyze the incidence and risk factors of SPC after HPV-related cancer. We identified 86 790 patients diagnosed with initial primary HPV-related cancer between 1973 and 2010 in the SEER database. Standardized incidence ratio (SIR) and cumulative incidence were calculated to assess the risk of SPC after HPV-related cancer. The SIR of SPC after HPV-related cancer was 1.60 (95% confidence interval [CI], 1.55-1.65) for male and 1.25 (95% CI, 1.22-1.28) for female. SIR of second primary HPV-related cancer (7.39 [95% CI, 6.26-8.68] male and 4.35 [95% CI, 4.04-4.67] female) was significantly higher than that of HPV-unrelated cancer (1.54 [95% CI, 1.49-1.60] male and 1.16 [95% CI, 1.13-1.19] female). The 5-year cumulative incidence of SPC was 7.22% (95% CI, 6.89-7.55%) for male and 3.72% (95% CI, 3.58-3.88%) for female. Risk factors for SPC included being married and having initial primary cancer (IPC) diagnosed at earlier stage for both genders, and IPC diagnosed at older age as well as surgery performed for female. Patients diagnosed with HPV-related cancer are more likely to develop another primary cancer, compared with the age-specific reference population.

SUMOylation of HSP27 regulates PKM2 to promote esophageal squamous cell carcinoma progression

A previous proteomic screening of differentially expressed biomarkers between Kazakh patients with esophageal squamous cell carcinoma (ESCC) and normal adjacent tissues demonstrated that heat shock protein 27 (HSP27) and pyruvate kinase isoenzyme M2 (PKM2) were both highly expressed in ESCC samples compared with normal controls. However, the regulatory association between HSP27 and PKM2 in ESCC remains elusive. In the present study, immunohistochemistry and immunoblotting were adopted to examine the expression of HSP27, PKM2 and other relevant biomarkers involved in epithelial‑to‑mesenchymal transition in clinical tissue samples. The interactions between proteins were detected by co‑immunoprecipitation (Co‑IP) assay and further confirmed by immunofluorescence assay. The growth and motility of ESCC cells were examined by MTT, Transwell and wound healing assays. Overexpression of HSP27 was found to be significantly associated with T‑cell classification, lymph node metastasis and poor prognosis in ESCC. In addition, HSP27 expression was significantly correlated with PKM2 expression in ESCC specimens. Functionally, knockdown of HSP27 inhibited the growth and motility of ESCC cells. Moreover, HSP27 was found to directly interact with small ubiquitin‑related modified protein 2/3 (SUMO2/3) in ESCC cell lines, as evidenced by Co‑IP and laser confocal imaging. In addition, downregulation of HSP27 was shown to decrease PKM2 and E‑cadherin expression. Knockdown of SUMO2/3 was observed to reduce the expression of HSP27, PKM2 and EMT‑related biomarkers. The results of the present study indicated that the SUMOylation of HSP27 enhances the proliferation, invasion and migration of ESCC cells via PKM2.

Epidemiology of HPV Infection and HPV-Related Cancers in Kazakhstan: a Review

Background: Cancer is one of the most prevalent causes of mortality worldwide. In the cervix it is considered to be caused by different high-risk human papillomavirus (HPV) types. Although many studies have already been conducted worldwide on the epidemiology of HPV infection and their oncogenic properties, limited data are available on HPV prevalence, incidence and genotype specific dissemination in Kazakhstan. Methods: To review the distribution of HPV infection, electronic databases (e.g. PubMed, Web of Science and Google Scholar) were searched for peer reviewed articles in English. The study was performed during June-July 2017 with a review of 39 relevant articles, published up to July 31, 2017. The following inclusion criteria were applied: general population data, cytology results available, and use of polymerase chain reaction (PCR) and/or Hybrid Capture® 2, Digene Corp., USA for HPV detection. Results: As reported in limited studies, the prevalence of HPV infection in Kazakhstan ranges from 43.8% to 55.8%. However, the scenario with regard to epidemiology of HPV related cancers in Kazakhstan is not very clear. One study reported a decline of laryngeal cancer observed during the recent years, whereas cervical cancer incidence has increased to about 3000 new cervical cancer cases, and about 1,000 cervical cancer deaths each year. Conclusion: The high incidence of cervical cancer with a significant mortality rate in Kazakhstan is evidence of HPV infection abundance despite an absence of HPV screening and low public awareness of the problem. Having a well-informed understanding of the role of HPV infection could enhance the public’s acceptance of screening and intervention programs to reduce morbidity and mortality in the country due to HPV infection. Thus, the purpose of this review article is to summarize the existing data, identifying directions for future research on HPV epidemiology and HPV-related diseases in Kazakhstan.

p53 expression but not p16(INK4A) correlates with human papillomavirus-associated esophageal squamous cell carcinoma in Kazakh population

Background

p16^INK4A expression has been used as a surrogate marker for human papillomavirus (HPV) infection in cervical cancer and head and neck cancer. p53 has also been reported as a feasible marker to identify HPV-positive oropharyngeal carcinoma and penile lesions. This study aimed to investigate p16^INK4A and p53 expression levels and their correlation with HPV status and clinical parameters in Kazakh patients with esophageal squamous cell carcinoma.

Methods

Immunohistochemical expression of p16^INK4A and p53 were evaluated in 163 cases of esophageal squamous cell carcinoma in Kazakh patients. The presence of HPV DNA was detected by polymerase chain reaction.

Results

p16^INK4A-positive expression was detected in 19.0 % of patients, and its expression was significantly correlated with a lower frequency of lymph node metastasis (p = 0.038). By contrast no significant association was found between p16^INK4A-positive expression and HPV status (correlation coefficient = -0.062, p = 0.499). p16^INK4A-positive expression did not affect the odds of tumors being HPV positive (odds ratio [OR] = 0.727 with 95 % confidence interval [CI] = 0.288–1.836). The sensitivity of p16^INK4A-positive expression as an HPV marker was 0.164, with a specificity of 0.788 and a positive predictive value of 0.391. p53-positive expression was present in 88.3 % of all cases. Although no significant correlation with available clinical parameters was found, a significantly inverse correlation was observed between p53 expression and HPV status (correlation coefficient = -0.186, p = 0.039). Moreover, p53-positive expression decreased the odds of tumors being HPV positive (OR = 0.292 with 95 % CI = 0.086–0.990). The sensitivity of p53-negative expression as an HPV marker was 0.179, with a specificity of 0.940 and a positive predictive value of 0.714. The overall HPV prevalence was high (45.5 %) in Kazakh patients, with no significant association between HPV positivity and available clinical parameters or combined p16^INK4A/p53 expression.

Conclusions

p16^INK4A-positive expression was associated with lymph node metastasis. Results indicate that p53-negative expression and not p16^INK4A-positive expression may be used as a marker for HPV status in ESCC; however, this finding requires further studies for validation.

Detection of human papillomavirus in esophageal and gastroesophageal junction tumors: A retrospective study by real-time polymerase chain reaction in an instutional experience from Turkey and review of literature

Esophageal cancer is a poor-prognosis malignancy that ranks eighth among all cancer types, and its prevalence shows differences among geographical regions. Although the most important risk factors for esophageal carcinoma are alcohol and smoking, viral infections, particularly HPV infection, are also considered among etiological agents. Our study aims to detect the presence of HPV in esophageal cancers in our patient population and to investigate its correlation with clinico-pathological parameters. We investigated the presence of HPV-DNA by real-time polymerase chain reaction in a total of 52 patients with esophageal cancer. Subtype analysis was performed in positive cases and was correlated with selected clinico-pathological parameters. Five (9.6%) of 52 tumor samples, 3 squamous cell carcinomas (3/33 cases) and 2 adenocarcinomas (2/19 cases), were HPV-DNA-positive. Subtype analysis could be performed in four HPV-DNA-positive cases, of which three were HPV type-39 and 1 was type-16. The Marmara region, where the present study was carried out, is a region with low-moderate risk for esophageal cancer, and the prevalence of HPV-DNA in these tumors is similar to the prevalence of HPV-DNA reported in the literature for regions with similar risk. In conclusion, we detected HPV DNA in a subset of esophageal and gastroesophageal junction tumors. HPV infection may have a role in esophageal carcinogenesis and high-risk HPV subtypes can particularly be considered among risk factors since the prevalence of high risk HPV infection has also been found to be increased in regions with a high risk for esophageal cancer compared to low-moderate risk regions.

Prevalence of human papillomavirus 16 in esophageal cancer among the Chinese population: a systematic review and meta-analysis

BACKGROUND AND AIM

No firm evidence of HPV infection in esophageal cancer has been established to date. The aim of this meta-analysis was to investigate the prevalence of HPV 16 in esophageal cancer in China, which had a high burden of the disease.

MATERIALS AND METHODS

Studies on HPV infection and esophageal cancer were identified and a random-effects model was used to pool the summary prevalence and corresponding 95% confidence intervals (CIs).

RESULTS

A total of 3,429 esophageal cancer cases were evaluated from 26 eligible studies in this meta-analysis. The summary estimate for HPV16 prevalence was 0.381 (95% CI: 0.283, 0.479). The prevalence varied by geographical areas of the study, publication year, HPV detection method and types of specimen. In sensitivity analysis, HPV 16 prevalence ranged from 0.368 (95% CI: 0.276, 0.460) to 0.397 (95% CI: 0.286, 0.508).

CONCLUSIONS

The results indicate a relatively high level of HPV 16 prevalence in esophageal cancer among Chinese population, although there was variation between different variables. Further studies are needed to elucidate the role of HPV in esophageal carcinogenesis with careful consideration of study design and laboratory detection method, providing more accurate assessment of the HPV status in esophageal cancer.

Human papillomavirus type-18 prevalence in oesophageal cancer in the Chinese population: a meta-analysis

Globally, the prevalence of oesophageal cancer cases is particularly high in China. Since 1982, oncogenic human papillomavirus (HPV) has been hypothesized as a risk factor for oesophageal cancer, but no firm evidence of HPV infection in oesophageal cancer has been established to date. We aimed to conduct a meta-analysis to estimate the high-risk HPV-18 prevalence of oesophageal cancer in the Chinese population. Eligible studies published from 1 January 2005 to 12 July 2014 were retrieved via computer searches of English and Chinese literature databases (including Medline, EMBASE, Chinese National Knowledge Infrastructure and Wanfang Data Knowledge Service Platform). A random-effects model was used to calculate pooled prevalence and corresponding 95% confidence intervals (CIs). A total of 2556 oesophageal cancer cases from 19 studies were included in this meta-analysis. Overall, the pooled HPV-18 prevalence in oesophageal cancer cases was 4·1% (95% CI 2·7-5·5) in China, 6·1% (95% CI 2·9-9·3) in fresh or frozen biopsies and 4·0% (95% CI 2·3-5·8) in paraffin-embedded fixed biopsies, 8·2% (95% CI 4·6-11·7) by the E6/E7 region and 2·2% (95% CI 0·9-3·6) by the L1 region of the HPV gene. This meta-analysis indicated that China has a moderate HPV-18 prevalence of oesophageal cancer compared to cervical cancer, although there is variation between different variables. Further studies are needed to elucidate the role of HPV in oesophagus carcinogenesis with careful consideration of study design and laboratory detection method, providing more accurate assessment of HPV status in oesophageal cancer.

Association between human papillomavirus (HPV) and oesophageal squamous cell carcinoma: a meta-analysis

SUMMARY

The oncogenic potential of human papillomaviruses (HPV) is well known in the context of cervical carcinoma; however, their role in the development of oesophageal squamous cell carcinoma (OSCC) is less clear. We aimed to determine the extent of the association between HPV infection and OSCC. A comprehensive literature search found 132 studies addressing HPV and OSCC in human cases, and a meta-analysis was performed using a random-effects model. There was evidence of an increased risk of OSCC in patients with HPV infection [odds ratio (OR) 2·69, 95% confidence interval (CI) 2·05-3·54]. The prevalence of HPV in OSCC was found to be 24·8%. There was an increased risk associated with HPV-16 infection (OR 2·35, 95% CI 1·73-3·19). Subgroup analyses showed geographical variance, with Asia (OR 2·94, 95% CI 2·16-4·00), and particularly China (OR 2·85, 95% CI 2·05-3·96) being high-risk areas. Our results confirm an increase in HPV infection in OSCC cases.

Systematic review with meta-analysis: the association between human papillomavirus infection and oesophageal cancer

BACKGROUND

Human papillomavirus (HPV) infection might be one of the potential risk factors for oesophageal cancer. However, the previous epidemiological findings were heterogeneous.

AIM

To explore the association between HPV infection and oesophageal cancer risk by means of meta-analysis.

METHODS

Studies on HPV infection and oesophageal cancer were identified, the prevalence of HPV infection and its association with oesophageal cancer risk were quantitatively summarised by meta-analysis.

RESULTS

A total of 8990 oesophageal squamous cell carcinoma (SCC) patients and 174 oesophageal adenocarcinomas patients were evaluated from 76 included studies. Summarised HPV prevalence in oesophageal SCC was 22.2% [95% confidence interval (CI), 18.3-26.7%], HPV-16 was the most frequently observed subtype with a summarised prevalence of 11.4% (95% CI: 8.2-15.7%). With respect to oesophageal adenocarcinoma, HPV prevalence was 35.0% (95% CI, 13.2-65.7%) and HPV-16 prevalence was 11.4% (95% CI: 8.2-15.7%). Due to the limited number of included studies on oesophageal adenocarcinoma, association analyses were performed to oesophageal SCC only. Significant association was observed between HPV infection and oesophageal SCC with a summarised odds ratio of 3.32 (95% CI, 2.26-4.87). According to HPV-16, the strength of the association was found to be 3.52 (95% CI, 2.04-6.07).

CONCLUSIONS

Human papillomavirus infection was observed to be associated with an increased risk of oesophageal SCC in this meta-analysis. However, due to the evident heterogeneity observed between the included studies and the strength of the association not as strong as observed for cervical cancer and laryngeal cancer, further studies are needed to clarify the relation and its underlying mechanisms.

Role of human papillomaviruses in esophageal carcinoma: an updated systematic review from 1982 to 2013

ABSTRACT: 

Tobacco, alcohol and betel quid are known etiological agents of esophageal squamous cell carcinoma (ESCC). A meta-analysis in 2012 and a literature update (1982–August 2013) identified 159 studies with a total of 11,310 ESCCs tested for the presence of human papillomaviruses (HPVs). HPV DNA was present in 30.3% of fESCCs, with substantial geographic differences. A recent meta-analysis of 21 case–control studies investigating the HPV–ESCC association showed that HPVs increase the risk of ESCC at least threefold. Vaccine-preventable HPV-16 and HPV-18 are the most commonly identified HPV types in ESCC in both low- and high-incidence settings. HPVs should now be seriously considered as etiological agents for at least a subset of ESCC, and more studies are needed to provide conclusive evidence that HPVs cause ESCC.

Heterozygote of PLCE1 rs2274223 increases susceptibility to human papillomavirus infection in patients with esophageal carcinoma among the Kazakh populations

The involvement of human papillomavirus (HPV) in the carcinogenesis of esophageal squamous carcinoma remains undetermined. However, three genome-wide association studies of esophageal cancer have identified a shared susceptibility locus at 10q23 (rs2274223: A5780G) in phospholipase C epsilon 1 (PLCE1). The current study aims to present a comprehensive and novel spectrum about the HPV genotype distribution of esophageal carcinoma in Kazakhs and assess its association with PLCE1 polymorphisms. The HPV genotypes in 183 patients with esophageal cancer and 89 controls selected from the Kazakh population were evaluated using the HPV gene chip. The PLCE1 rs2274223 variant was genotyped in esophageal carcinoma patients by MALDI-ToF Mass Spectrometry. The presence of seven HPV genotypes in esophageal carcinoma tissues-including HPV 16, 18, 35, 52, 6, 11, 43-was significantly higher at 31.7% than those in controls at 9.0% (P < 0.001). Such presence was strongly associated with increased risk of esophageal carcinoma (OR 4.70; 95% CI 2.13-10.36). Among all HPV genotypes detected, HPV16 was the most common genotype identified (29.0%, OR 4.13; 95% CI 1.87-9.13), which is significantly associated with well-differentiated esophageal carcinoma (P = 0.037). HPV-positive patients were generally younger than HPV-negative patients (70.1% vs. 29.3%, P = 0.013). PLCE1 rs2274223 genotypes AG and AG/GG were significantly associated with HPV-positive patients with esophageal carcinoma (OR 2.05, 95% CI 1.03-4.08 and OR 1.98, 95% CI 1.02-3.84, respectively). These findings suggest that heterozygote of PLCE1 rs2274223 increases susceptibility to HPV infection in patients with esophageal carcinoma among the Kazakh populations.

Human papillomavirus types 16 and 18 in esophagus squamous cell carcinoma: a meta-analysis

PURPOSE

A possible carcinogenic role of human papillomavirus (HPV) has been investigated in esophageal squamous cell carcinoma (ESCC) for nearly 30 years with mixed results. We performed a meta-analysis to assess the prevalence of "high-risk" HPV, HPV-16/18, in this disease. We also evaluated the association between infection with HPV-16/18 and ESCC risk by meta-analysis of case-control studies.

METHODS

Eligible studies published up to September 30, 2012 were retrieved via both computer searches of MEDLINE and EMBASE and manual review of references. A random-effects model was used to calculate summary prevalence and odds ratios (ORs) and corresponding 95% confidence intervals (CIs).

RESULTS

A total of 5755 cases of ESCC from 68 studies were included in this meta-analysis. Overall, 11.67% (95% CI, 7.74%-16.21%) of ESCC cases harbored HPV-16 and 1.82% (95% CI, 0.90%-2.95%) harbored HPV-18. In addition, meta-analysis of 10 case-control studies showed a significant increase in ESCC risk with HPV-16 infection (summary ORs = 3.55; 95% CIs, 2.05%-6.14%). However, this increased risk in ESCC was not made for HPV-18 infection (summary ORs = 1.25; 95% CIs, 0.46%-3.43%).

CONCLUSIONS

This meta-analysis indicated that HPV-16 and -18 can be detected in ESCC. HPV-16, but not HPV-18, is significantly associated with the risk of ESCC. However, it is early to conclude that both types of HPV are involved in esophageal carcinogenesis.

Viral load of HPV 16/18 in esophageal squamous cell carcinoma in three ethnic groups living in Xinjiang Autonomous Region, China

To investigate the viral load of human papillomavirus (HPV) in esophageal squamous cell carcinoma (ESCC) patients from three ethnic groups in Xinjiang. Using Gp5+/Gp6+ consensus primers, the prevalence of HPV DNA was examined in 253 paraffin-embedded ESCC samples. The presence and viral load of HPV 16 and HPV 18 were detected in Kazakhs, Uygurs and Hans using type-specific primers by quantitative real-time PCR (qRT-PCR). Among the 253 ESCC samples, 52 cases were positive for HPV DNA, all the 52 positive cases displayed HPV 16 infection, and six of the 52 cases were co-infected by HPV 16 and 18. HPV 16-positive rate and viral load were higher in lesions, and was inversely correlated with differentiation grades. However, there was no statistic significance among different differentiation grades. Also, there were no significant difference between detection rates of HPV types, viral load and age, gender, ethnic group, and lymph node metastasis. HPV 16 and HPV 18 genotypes could simultaneously be detected in ESCC specimens in three main ethnic groups in Xinjiang. The viral load of HPV 16 is higher in the ESCC lesions, and is inversely correlated with the differentiation grades. These observations reinforce the suggestion that HPV infection may involved in ESCC carcinogenesis; however, high prevalence or viral load of HPV infection does not seem to be related with high incidence of ESCC in Kazakhs, which may be the one element among the multiple risk factors contributing to ESCC.

Role of human papillomaviruses in esophageal squamous cell carcinoma

Esophageal cancer (EC) is responsible for almost half a million deaths worldwide annually and has a multifactorial etiology, which may account for its geographical variation in incidence. In the last 30 years the potential of human papillomaviruses (HPV) as oncogenes or co-factors in the tumorigenic process of esophageal squamous cell carcinoma (ESCC) has been widely studied. While the etiology of HPV in cervical and certain other anogenital and aerodigestive cancers has been established, results regarding its role in EC have been largely inconclusive. A causal association can be evaluated only with a case-control study, where normal controls are compared to ESCC cases for the presence of HPV. We reviewed all studies investigating ESCC tissue for HPV DNA and identified 139 that met our inclusion criteria, of which only 22 were case-control studies. Our results support previous findings of higher levels of HPV detection in high-risk ESCC regions than in areas of low risk. In addition, we confirm that the role of HPV in ESCC remains unclear, despite an accumulation of studies on the subject. The variations in investigative technique, study design and sample types tested may account for the lack of consistency in results. There is a need for a meta-analysis of all case-control studies to date, and for large, well-designed case-control studies with adequate power to investigate the association. The potential benefits of prophylactic HPV vaccines could be evaluated if HPV is identified as an etiological factor in EC, highlighting the need for further research in this area.

Geographic origin is a significant determinant of human papillomavirus prevalence in oesophageal squamous cell carcinoma: systematic review and meta-analysis

BACKGROUND

Since the first reports in 1982 suggesting an aetiological role for human papillomavirus (HPV) in a subset of oesophageal squamous cell carcinomas (ESCC), the literature reporting HPV detection in ESCC has expanded rapidly. However no formal meta-analysis of this literature has been published yet. The objective of this study was to perform a systematic review and formal meta-analysis of the literature reporting HPV detection in ESCC.

METHODS

MEDLINE and Current Contents were searched through March 2012. The effect size was calculated as event rates and their 95% confidence interval (95% CI), with homogeneity testing using Cochran's Q and I² statistics. Meta-regression was used to test the impact of study-level covariates (HPV detection method, geographic origin of study) on effect size, and potential publication bias was estimated using funnel plot symmetry (Begg and Mazumdar rank correlation, Egger's regression, and Duval and Tweedie's trim and fill method).

RESULTS

Of the 1177 abstracts found, 152 studies were determined to be eligible for this meta-analysis. These 152 studies covered a total of 10,234 ESCC cases, analysed by different HPV detection methods in different geographic regions. Of these 10,234 cases, 3135 (30.6%) tested HPV-positive, translating to an effect size of 0.372 (95% CI 0.360-0.384; fixed effects model) and 0.290 (95% CI 0.251-0.31; random effects model). When stratified by HPV detection technique, there was a significant heterogeneity between the studies, but importantly, the between-strata summary comparison was not significant (random effects model; p = 0.440). In contrast, there was significant heterogeneity between the studies from the different geographic regions. In the maximum likelihood meta-regression, HPV detection method was not a significant study-level covariate, in contrast to the geographic origin of the study, which had a significant impact (p = 0.00005) on the summary effect size estimates. No evidence for significant publication bias was found in funnel plot symmetry testing. In the sensitivity analysis, all meta-analytic results appeared robust to all (n = 151) one-by-one study removals.

CONCLUSIONS

These meta-analysis results indicate that the reported wide variability in HPV detection rates in ESCC is not due to the HPV detection techniques, but is explained by the geographic origin of the study. These data substantiate the recently elaborated concept that ESCC might have a different aetiology in low-incidence and high-incidence geographic regions, HPV playing an important role only in the latter.

High-risk human papillomavirus in esophageal squamous cell carcinoma

BACKGROUND

Although most cases of esophageal squamous cell carcinoma (ESCC) in western populations have been attributed to high levels of exposure to tobacco and alcohol, infectious agents have been postulated as possible causes, particularly human papillomavirus (HPV).

METHODS

To explore this issue, we analyzed HPV DNA prevalence and HPV types together with lifestyle factors, in relation to tumor stage and survival in a low-incidence population. Archived tumor samples from a nationwide cohort of 222 ESCC patients were tested for the presence of HPV DNA by PCR; positive samples were sequenced to determine HPV type, and p16(INK4a) status was assessed by immunohistochemistry.

RESULTS

Of 222 ESCC patients, 8 tested HPV positive (prevalence, 3.6%; 95% confidence interval, 1.1-6.1%), of which 6 were HPV-16 positive and 2 were HPV-35 positive. Four of the eight HPV-positive tumors overexpressed p16(INK4a). None of 55 normal esophageal tissue samples from healthy participants had any detectable HPV. Although the numbers were low, it seemed that patients with HPV-positive ESCC tumors were younger than those with HPV-negative tumors (mean age, 60.8 versus 65.3 years, P = 0.18) and had higher body mass index (BMI) throughout life (mean current BMI of 25.1 for HPV positive, 22.2 for HPV negative, P = 0.08; mean BMI at 20 years of 25.8 for HPV positive, 22.1 for HPV negative, P = 0.003). We found no difference between patients with HPV-positive and HPV-negative tumors with respect to other lifestyle factors.

CONCLUSIONS

These findings suggest a very low prevalence of HPV DNA in human ESCC.

IMPACT

HPV is very unlikely to be a common cause of ESCC in Australia.

Northwestern China: a place to learn more on oesophageal cancer. Part one: behavioural and environmental risk factors

Oesophageal squamous cell carcinoma (OSCC) remains a public health problem in many countries, especially in emerging and developing countries. Epidemiology of OSCC is characterized by marked differences in prevalence between countries/regions/ethnical groups. The highest incidence in the world is reached by populations living in specific areas of northwestern Xinjiang, China where age-adjusted mortality may reach 150 of 100 000. In fact, there are also marked differences among the various geographical areas and the various ethnic groups within the region, which suggests specific risk factors. Behavioural factors include those factors which are common to all 'high-risk populations', such as tobacco smoking and alcohol drinking. However, the very unusual sex ratio (1.2 : 1.0) and young age range of OSCC occurrence suggests the involvement of additional early risk factors shared by males and females, and which are different from those studied in other 'high-risk' areas of the world, including China, such as LinXian area. These include drinking very hot and salted tea, boiled with milk; a diet rich in meat, especially salted, dry and/or smoked meat, and dairy products; and a diet poor in fresh fruit and vegetables. The combination of hot drinks (such as milk, tea and soups) and high-degree spirit drinks, and hard food (bread, meat and cheese), together with poor oral hygiene and tooth loss, is likely to add mechanical injury of the oesophagus to other factors linked to climate characteristics of the area (drought) and dietary habits, which promote a sodium and nitrosamine-rich diet. Association of early and severe hypertension in the same populations at high risk of OSCC might likely raise more attention. Human papilloma virus (HPV) infection, and especially HPV 16/18 E6/E7, with gene mutations and association with p53 overexpression, may contribute to the extremely high incidence of OSCC observed in Xinjiang, and could be accessible to prevention. Infection may especially be a crucial additional factor in the Uygur population in which not only HPV infection but also infection with other oncogenic viruses, such as HHV8, are highly prevalent. Genetic polymorphism might interact with viruses and/or viral products to promote carcinogenesis. These observations in northwestern China suggest that usually neglected factors, such as sodium excess and viral infection, could be taken into more account when studying OSCC risk factors in other parts of the world, especially Europe.

Vaccination against human papilloma virus (HPV): epidemiological evidence of HPV in non-genital cancers

Recently, the vaccine against human papillomavirus (HPV) was introduced in the national vaccination programmes of several countries worldwide. The established association between HPV and the progression of cervical neoplasia provides evidence of the expected protection of the vaccine against cervical cancer. During the last two decades several studies have also examined the possible involvement of HPV in non-genital cancers and have proposed the presence of HPV in oesophageal, laryngeal, oropharyngeal, lung, urothelial, breast and colon cancers. The possible involvement of HPV in these types of cancer would necessitate the introduction of the vaccine in both boys and girls. However, the role of HPV in the pathogenesis of these types of cancer has yet to be proven. Moreover, the controversial evidence of the possible impact of the vaccination against HPV in the prevention of non-genital cancers needs to be further evaluated. In this review, we present an overview of the existing epidemiological evidence regarding the detection of HPV in non-genital cancers.

Relationship between human papillomavirus 16 and esophageal squamous cell carcinoma in Uygur population in Xinjiang Uygur Autonomous Region

AIM: To investigate the infection rate of human papillomavirus 16 (HPV16) in Uygur patients with esophageal squamous cell carcinoma in Xinjiang.

METHODS: Eighty-two paraffin-embedded specimens of esophageal carcinoma and 80 tumor-adjacent specimens were used in the study. The presence of HPV16 in these specimens was detected by high-sensitivity polymerase chain reaction (PCR) using the type-specific E6 primers.

RESULTS: The infection rates of HPV16 in esophageal squamous cell carcinoma and tumor-adjacent tissue were 31.7% (26/82) and 12.5% (10/80), respectively, showing significant difference between the two groups. HPV16 infection was not correlated with patient's age and sex as well as pathological differentiation and clinical stage of the carcinoma (χ² = 0.301, 0.149, 2.876 and 0.105, respectively; all P > 0.05).

CONCLUSION: HPV 16 infection is possibly correlated with esophageal squamous cell carcinoma in Uygur population in Xinjiang but showed no correlation with patient's age and sex as well as pathological differentiation and clinical stage of the carcinoma.

The incidence and risk of developing a second primary esophageal cancer in patients with oral and pharyngeal carcinoma: a population-based study in Taiwan over a 25 year period

BACKGROUND

The incidence of oral and pharyngeal (including oral cavity, oropharynx and hypopharynx) carcinoma increases rapidly in Asia and South Pacific because of betel quid chewing. Thus far, large-scale epidemiological studies are not available yet to stratify these patients by their risks of developing a second primary cancer in the digestive tract including esophagus, stomach, colon, and rectum.

METHODS

A population-based study was conducted using the database from the Taiwan National Cancer Registry for the period 1979-2003. We quantified standardized incidence ratios (SIRs) and cumulative incidence of second primary cancers among 33,787 patients with initial diagnoses of oral and pharyngeal carcinoma.

RESULTS

Among these four digestive tract organs, the esophagus was the only site of second cancer with excess risk in patients with oral and pharyngeal carcinoma. The incidence and risk of developing a second primary esophageal cancer differed by the site of the primary index tumor, most frequently seen in hypopharyngeal cancer (71/4,218 = 1.68%, SIR = 22.76, 95% CI 17.77-28.70), followed by oropharyngeal cancer (30/3,403 = 0.88%, SIR = 14.29, 95% CI 9.64-20.39) and the least in oral cavity cancer (99/26,166 = 0.38%, SIR = 5.57, 95% CI 4.53-6.78). In addition, the risk was extraordinarily high for patients with a follow-up interval

CONCLUSION

The present study represents the first population-based study in Asia attempting to stratify the patients of oral and pharyngeal carcinoma by their risk of developing a second esophageal cancer. It helps identify patients at high risk and tailor the application of intense follow-up surveillance to the estimated risk in each individual case.

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MESH Headings

• Adult
• Aged
• Aged, 80 and over
• Carcinoma, Squamous Cell/epidemiology
• Esophageal Neoplasms/epidemiology
• Female
• Follow-Up Studies
• Humans
• Incidence
• Male
• Middle Aged
• Mouth Neoplasms/epidemiology
• Neoplasms, Second Primary/epidemiology
• Pharyngeal Neoplasms/epidemiology
• Population Groups/statistics & numerical data
• Registries/statistics & numerical data
• Risk Factors
• Taiwan/epidemiology
• Young Adult

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Affiliation(s)

Kuan-Der Lee Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan, Republic of China Department of Medicine and Graduate Institute of Clinical Medical Sciences, Chang Gung University, Tao-Yuan Chang Gung Institute of Technology, Chia-yi Campus, Chiayi, Taiwan, Republic of China
Chang-Hsien Lu Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan, Republic of China Department of Medicine and Graduate Institute of Clinical Medical Sciences, Chang Gung University, Tao-Yuan Chang Gung Institute of Technology, Chia-yi Campus, Chiayi, Taiwan, Republic of China
Ping-Tsung Chen Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan, Republic of China Department of Medicine and Graduate Institute of Clinical Medical Sciences, Chang Gung University, Tao-Yuan Chang Gung Institute of Technology, Chia-yi Campus, Chiayi, Taiwan, Republic of China
Chunghuang Hubert Chan Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan, Republic of China Department of Medicine and Graduate Institute of Clinical Medical Sciences, Chang Gung University, Tao-Yuan Chang Gung Institute of Technology, Chia-yi Campus, Chiayi, Taiwan, Republic of China
Jen-Tsun Lin Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan, Republic of China Department of Medicine and Graduate Institute of Clinical Medical Sciences, Chang Gung University, Tao-Yuan Chang Gung Institute of Technology, Chia-yi Campus, Chiayi, Taiwan, Republic of China
Cih-En Huang Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan, Republic of China
Chih-Cheng Chen Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi, Taiwan, Republic of China Department of Medicine and Graduate Institute of Clinical Medical Sciences, Chang Gung University, Tao-Yuan Chang Gung Institute of Technology, Chia-yi Campus, Chiayi, Taiwan, Republic of China
Min-Chi Chen Department of Public Health and Biostatistics Consulting Center, School of Medicine, Chang Gung University, Tao-Yuan, Taiwan, Republic of China

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The EVER proteins as a natural barrier against papillomaviruses: a new insight into the pathogenesis of human papillomavirus infections

Infections by human papillomaviruses (HPVs) are the most frequently occurring sexually transmitted diseases. The crucial role of genital oncogenic HPV in cervical carcinoma development is now well established. In contrast, the role of cutaneous HPV in skin cancer development remains a matter of debate. Cutaneous beta-HPV strains show an amazing ubiquity. The fact that a few oncogenic genotypes cause cancers in patients suffering from epidermodysplasia verruciformis is in sharp contrast to the unapparent course of infection in the general population. Our recent investigations revealed that a natural barrier exists in humans, which protects them against infection with these papillomaviruses. A central role in the function of this HPV-specific barrier is played by a complex of the zinc-transporting proteins EVER1, EVER2, and ZnT-1, which maintain cellular zinc homeostasis. Apparently, the deregulation of the cellular zinc balance emerges as an important step in the life cycles not only of cutaneous but also of genital HPVs, although the latter viruses have developed a mechanism by which they can break the barrier and impose a zinc imbalance. Herein, we present a previously unpublished list of the cellular partners of EVER proteins, which points to future directions concerning investigations of the mechanisms of action of the EVER/ZnT-1 complex. We also present a general overview of the pathogenesis of HPV infections, taking into account the latest discoveries regarding the role of cellular zinc homeostasis in the HPV life cycle. We propose a potential model for the mechanism of function of the anti-HPV barrier.

How strong is the evidence that solar ultraviolet B and vitamin D reduce the risk of cancer?: An examination using Hill's criteria for causality

The ultraviolet-B (UVB)-vitamin D-cancer hypothesis was proposed in 1980. Since then, several ecological and observational studies have examined the hypothesis, in addition to one good randomized, controlled trial. Also, the mechanisms whereby vitamin D reduces the risk of cancer have been elucidated. This report aims to examine the evidence to date with respect to the criteria for causality in a biological system first proposed by Robert Koch and later systematized by A. Bradford Hill. The criteria of most relevance are strength of association, consistency, biological gradient, plausibility/mechanisms and experimental verification. Results for several cancers generally satisfy these criteria. Results for breast and colorectal cancer satisfy the criteria best, but there is also good evidence that other cancers do as well, including bladder, esophageal, gallbladder, gastric, ovarian, rectal, renal and uterine corpus cancer, as well as Hodgkin's and non-Hodgkin's lymphoma. Several cancers have mixed findings with respect to UVB and/or vitamin D, including pancreatic and prostate cancer and melanoma. Even for these, the benefit of vitamin D seems reasonably strong. Although ecological and observational studies are not generally regarded as able to provide convincing evidence of causality, the fact that humanity has always existed with vitamin D from solar UVB irradiance means that there is a wealth of evidence to be harvested using the ecological and observational approaches. Nonetheless, additional randomized, controlled trials are warranted to further examine the link between vitamin D and cancer incidence, survival and mortality.