Detection of Human papillomavirus and cellular regulators p16INK4a, p53, and NF-kappaB in penile cancer cases in Kenya

Human Papillomavirus Infection in Penile Cancer: Multidimensional Mechanisms and Vaccine Strategies

Penile cancer (PC) is a rare male malignant tumor, with early lymph node metastasis and poor prognosis. Human papillomavirus (HPV) plays a key role in the carcinogenesis of PC. This review aims to summarize the association between HPV infection and PC in terms of virus-host genome integration patterns (the disrupted regions in the HPV and PC genome), genetic alterations, and epigenetic regulation (methylation and microRNA modification) occurring in HPV and PC DNA, as well as tumor immune microenvironment reprogramming. In addition, the potential of HPV vaccination strategies for PC prevention and treatment is discussed. Understanding of the HPV-related multidimensional mechanisms and the application of HPV vaccines will promote rational and novel management of PC.

The role of infections in the causation of cancer in Kenya

Cancer constitutes a major health care burden in the world today with the situation worsening in resource poor settings as seen in most Sub-Saharan African (SSA) countries. Infections constitute by far the most common risk factors for cancer in SSA and being a typical country in this region, Kenya has experienced an upsurge in the incidence of various types of cancers in the last few decades. Although there is limited population-based data in Kenya of infections-associated cancers, this review provides an up-to-date literature-based discussion on infections-associated cancers, their pathogenesis, and preventive approaches in the country. The primary infectious agents identified are largely viral (human immunodeficiency virus, human papillomavirus (HPV), Kaposi's sarcoma-associated herpes virus, Epstein-Barr virus, hepatitis B virus (HBV), hepatitis C virus), and also bacterial: Helicobacter pylori and parasitic: Schistosomiasis haematobium. Cancers associated with infections in Kenya are varied but the predominant ones are Non-Hodgkin lymphoma, Kaposi's sarcoma, Hodgkin lymphoma, Burkitt's lymphoma, cervical, liver, and gastric cancers. The mechanisms of infections-induced carcinogenesis are varied but they mainly seem to stem from disruption of signaling, chronic inflammation, and immunosuppression. Based on our findings, actionable cancer-preventive measures that are economically feasible and aligned with existing infrastructure in Kenya include screening and treatment of infections, implementation of cancer awareness and screening, and vaccination against infections primarily HBV and HPV. The development of vaccines against other infectious agents associated with causation of cancer remains also as an important goal in cancer prevention.

Single-Center Analysis of Human Papillomavirus Infection and P16INK4A Expression among Korean Patients with Penile Cancer

Purpose

This study aimed to evaluate the statuses of P16INK4A expression and human papillomavirus (HPV) infection among patients with penile cancer at a single Korean institution.

Patients and Methods

Fourteen patients with penile cancer at our center were retrospectively identified and their clinicopathological data were analyzed. The patients' HPV and P16INK4A expression status (a known tumor suppressor protein) were tested using genotyping with a DNA chip assay and immunohistochemical staining, respectively. The results regarding HPV status were compared to those from another Asian study.

Results

The mean age at diagnosis was 60 years (range: 34–86 years). The median tumor size was 3.0 cm (range: 0.6–4.7 cm). Ten tumors were located on the penile glans. Five patients tested positive for HPV DNA (5/14, 36%) and all cases involved HPV type 16 (5/5, 100%). Positive expression of P16INK4A was observed in 6 cases (6/14, 43%). Among the HPV positive cases, 80% of cases (4/5) were also positive for P16INK4A. The prevalence of HPV infection in our study (36%) was higher than in a previous Asian study (23%).

Conclusions

This is the first study to evaluate the prevalence of HPV infection and P16INK4A expression among patients with penile cancer at a single Korean institution. The prevalence of HPV (36%) was slightly higher than the results from a previous Asian study. Additional multi-center studies are needed to better understand penile cancer in Korea and to identify biomarkers that can determine high-risk cases and predict their prognosis.

Prevalence of human papillomavirus DNA and p16INK4a in penile cancer and penile intraepithelial neoplasia: a systematic review and meta-analysis

BACKGROUND

Although previous meta-analyses have examined human papillomavirus (HPV) DNA prevalence in penile cancer, none, to our knowledge, have assessed pooled HPV DNA prevalence in penile intraepithelial neoplasia or p16^INK4a percent positivity in penile cancer and penile intraepithelial neoplasia. Therefore, we aimed to examine the prevalence of HPV DNA and p16^INK4a positivity in penile cancer and penile intraepithelial neoplasia worldwide.

METHODS

In this systematic review and meta-analysis, we searched PubMed, Embase, and the Cochrane Library until July 24, 2017, for English-language articles published from Jan 1, 1986, onwards reporting the prevalence of HPV DNA and p16^INK4a positivity, either alone or in combination, in at least five cases of penile cancer or penile intraepithelial neoplasia. Only studies that used PCR or hybrid capture for the detection of HPV DNA and immunohistochemical staining or methylation for the detection of p16^INK4a were included. Data were extracted and subsequently crosschecked, and inconsistencies were discussed to reach consensus. Using random-effects models, we estimated the pooled prevalence and 95% CI of HPV DNA and p16^INK4a positivity in penile cancer and penile intraepithelial neoplasia, stratifying by histological subtype and HPV DNA or p16^INK4a detection method. Type-specific prevalence of HPV6, HPV11, HPV16, HPV18, HPV31, HPV33, and HPV45 in penile cancer was estimated.

FINDINGS

Our searches identified 1836 non-duplicate records, of which 73 relevant papers (71 studies) were found to be eligible. The pooled HPV DNA prevalence in penile cancer (52 studies; n=4199) was 50·8% (95% CI 44·8-56·7; I²=92·6%, p_{heterogeneity}<0·0001). A high pooled HPV DNA prevalence was seen in basaloid squamous cell carcinomas (84·0%, 95% CI 71·0-93·6; I²=48·0%, p_{heterogeneity}=0·0197) and in warty-basaloid carcinoma (75·7%, 70·1-81·0; I²=0%, p_{heterogeneity}=0·52). The predominant oncogenic HPV type in penile cancer was HPV16 (68·3%, 95% CI 58·9-77·1), followed by HPV6 (8·1%, 4·0-13·7) and HPV18 (6·9%, 2·9-12·4). The pooled HPV DNA prevalence in penile intraepithelial neoplasia (19 studies; n=445) was 79·8% (95% CI 69·3-88·6; I²=83·2%, p_{heterogeneity}<0·0001). The pooled p16^INK4a percent positivity in penile cancer (24 studies; n=2295) was 41·6% (95% CI 36·2-47·0; I²=80·6%, p_{heterogeneity}<0·0001), with a high pooled p16^INK4a percent positivity in HPV-related squamous cell carcinoma (85·8%, 95% CI 72·1-95·4; I²=56·4%, p_{heterogeneity}=0·0011) as compared with non-HPV-related squamous cell carcinoma (17·1%, 7·9-29·1; I²=78·3%, p_{heterogeneity}<0·0001). Moreover, among HPV-positive cases of penile cancer, the p16^INK4a percent positivity was 79·6% (95% CI 65·7-90·7; I²=89·9%, p_{heterogeneity}<0·0001), compared with 18·5% (9·6-29·6; I²=89·3%, p_{heterogeneity}<0·0001) in HPV-negative penile cancers. The pooled p16^INK4a percent positivity in penile intraepithelial neoplasia (six studies; n=167) was 49·5% (95% CI 18·6-80·7).

INTERPRETATION

A large proportion of penile cancers and penile intraepithelial neoplasias are associated with infection with HPV DNA (predominantly HPV16), emphasising the possible benefits of HPV vaccination in men and boys.

FUNDING

None.

P16INK4a expression in patients with penile cancer

BACKGROUND

Infection with human papillomavirus (HPV) is reported to be present in 30-50% of penile cancer cases. The immunohistochemical test for p16INK4a is used as an indicator of the presence of HPV and as a prognostic marker for squamous cell carcinomas in various sites. However, the role of this marker in penile carcinoma has not yet been completely elucidated. The aim of this study was to analyze whether the expression of p16INK4a is associated with the presence of HPV, histological parameters, and survival in penile cancer.

METHODS

A study was conducted from 2014 to 2016 that included 55 patients with penile carcinoma. HPV DNA was detected through PCR using fresh tumor tissue, and immunohistochemistry was performed for analysis of p16INK4a protein using paraffin-embedded tissue. Evaluation of histological parameters was performed following complete embedding of the tumor tissue in paraffin.

RESULTS

HPV DNA (low-risk and high-risk genotypes) was found in 49 (89.1%) cases, and 46/49 (93.9%) showed high-oncogenic risk HPV (HR-HPV). Of the 22 cases positive for p16INK4a, HR-HPV DNA was present in 21 (95.5%) (p = 0.032). Regarding histological parameters, p16INK4a and HR-HPV were significantly associated only with tumor subtype (p = 0.036 and p = 0.032, respectively); all carcinomas with basaloid characteristics were positive for p16INK4a. Although HPV+ patients had a higher disease-free survival (p <0.001), p16INK4a expression was not associated with patient survival.

CONCLUSIONS

Our study, using fresh tissue samples, showed the highest incidence of HPV compared to that observed in the literature. Expression of the p16INK4a protein was significantly associated with the presence of HR-HPV and this expression may serve as a marker for the presence of the virus. The p16INK4a protein was not associated with the histological prognostic parameters, with the exception of tumor subtype, nor with patient survival. In the results, we showed that the objective of the present study was reached.

The burden of HPV associated cancers in two regions in Nigeria 2012-2014

INTRODUCTION

HPV attributable cancers are the second most common infection-related cancers worldwide, with much higher burden in less developed regions. There are currently no country-specific estimates of the burden of these cancers in Nigeria just like many other low and middle income countries.

METHODS

In this study, we quantified the proportion of the cancer burden in Nigeria that is attributable to HPV infection from 2012 to 2014 using HPV prevalence estimated from previous studies and data from two population based cancer registries (PBCR) in Nigeria. We considered cancer sites for which there is strong evidence of an association with HPV infection based on the International Agency for Research on Cancer (IARC) classification. We obtained age and sex-specific estimates of incident cancers and using the World Standard Population, we derived age standardized incidence (ASR) rates for each cancer type by categories of sex, and estimated the population attributable fractions (PAF).

RESULTS

The two PBCR reported 4336 new cancer cases from 2012 to 2014. Of these, 1627 (37.5%) were in males and 2709 (62.5%) in females. Some 11% (488/4336) of these cancers were HPV associated; 2% (38/1627) in men and 17% (450/2709) in women. Of the HPV associated cancers, 7.8% occurred in men and 92.2% in women. The ASRs for HPV associated cancers was 33.5 per 100,000; 2.3 and 31.2 per 100,000 in men and women respectively. The proportion of all cancers attributable to HPV infection ranged from 10.2 to 10.4% (442-453 of 4336) while the proportion of HPV associated cancers attributable to HPV infection ranged from 90.6% to 92.8% (442-453 of the 488 cases). In men, 55.3% to 68.4% of HPV associated cancers were attributable to HPV infection compared to 93.6% to 94.8% in women. The combined ASR for HPV attributable cancers ranged from 31.0 to 31.7 per 100,000. This was 1.4 to 1.7 per 100,000 in men and 29.6 to 30.0 per 100,000 in women. In women, cervical cancer (n=392, ASR 28.3 per 100,000) was the commonest HPV attributable cancer, while anal cancer (n=21, ASR 1.2 per 100,000) was the commonest in men.

CONCLUSIONS

HPV attributable cancers constitute a substantial cancer burden in Nigerian women, much less so in men. A significant proportion of cancers in Nigerian women would be prevented if strategies such as HPV DNA based screening and HPV vaccination are implemented.

Burden of Cancers Attributable to Infectious Agents in Nigeria: 2012-2014

Introduction

Infections by certain viruses, bacteria, and parasites have been identified as risk factors for some cancers. In Nigeria, like many other developing countries, infections remain a leading cause of morbidity and mortality. While there are data on the incidence of different cancers in Nigeria, there has been no study of cancers attributable to infections. This study was carried out to determine the burden of cancers attributable to infections using data from two population-based cancer registries (PBCRs) in Nigeria.

Methods

We obtained data on cancers associated with EBV, human papillomavirus (HPV), hepatitis B and C, HIV, HHV8, Helicobacter pylori, and Schistosoma spp. from the databases of Abuja and Enugu cancer registries in Nigeria. We used population-attributable fraction for infections-associated cancers in developing countries that are based on prevalence data and relative risk estimates from previous studies.

Results

The PBCRs reported 4,336 incident cancer cases [age standardized incidence rate (ASR) 113.9 per 100,000] from 2012 to 2014, of which 1,627 (37.5%) were in males and 2,709 (62.5%) were in females. Some 1,030 (23.8%) of these cancers were associated with infections (ASR 44.4 per 100,000), while 951 (22.0%) were attributable to infections (ASR 41.6 per 100,000). Cancers of the cervix (n = 392, ASR 28.3 per 100,000) and liver (n = 145, ASR 3.4 per 100,000); and non-Hodgkin’s lymphoma (n = 110, ASR 2.5 per 100,000) were the commonest infections-associated cancers overall. The commonest infectious agents associated with cancers in this population were HPV, EBV, hepatitis B and C, HIV, and HHV8.

Conclusion

Our results suggest that 23.8% of incident cancer cases in this population were associated with infections, while 22.0% were attributable to infections. The infections attributable cancers are potentially preventable with strategies, such as vaccination, risk factor modification, or anti-infective treatment.

The burden of human papillomavirus infections and related diseases in sub-saharan Africa

Despite the scarcity of high quality cancer registries and lack of reliable mortality data, it is clear that human papillomavirus (HPV)-associated diseases, particularly cervical cancer, are major causes of morbidity and mortality in sub-Saharan Africa (SSA). Cervical cancer incidence rates in SSA are the highest in the world and the disease is the most common cause of cancer death among women in the region. The high incidence of cervical cancer is a consequence of the inability of most countries to either initiate or sustain cervical cancer prevention services. In addition, it appears that the prevalence of HPV in women with normal cytology is higher than in more developed areas of the world, at an average of 24%. There is, however, significant regional variation in SSA, with the highest incidence of HPV infection and cervical cancer found in Eastern and Western Africa. It is expected that, due to aging and growth of the population, but also to lack of access to appropriate prevention services and the concomitant human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) epidemic, cervical cancer incidence and mortality rates in SSA will rise over the next 20 years. HPV16 and 18 are the most common genotypes in cervical cancer in SSA, although other carcinogenic HPV types, such as HPV45 and 35, are also relatively more frequent compared with other world regions. Data on other HPV-related anogenital cancers including those of the vulva, vagina, anus, and penis, are limited. Genital warts are common and associated with HPV types 6 and 11. HIV infection increases incidence and prevalence of all HPV-associated diseases. Sociocultural determinants of HPV-related disease, as well as the impact of forces that result in social destabilization, demand further study. Strategies to reduce the excessive burden of HPV-related diseases in SSA include age-appropriate prophylactic HPV vaccination, cervical cancer prevention services for women of the reproductive ages, and control of HIV/AIDS. This article forms part of a regional report entitled "Comprehensive Control of HPV Infections and Related Diseases in the Sub-Saharan Africa Region" Vaccine Volume 31, Supplement 5, 2013. Updates of the progress in the field are presented in a separate monograph entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Overexpression of ANXA1 in penile carcinomas positive for high-risk HPVs

The incidence of penile cancer varies between populations but is rare in developed nations. Penile cancer is associated with a number of established risk factors and associated diseases including phimosis with chronic inflammation, human papillomavirus (HPV) infection, poor hygiene and smoking. The objective of this study was to identify genes related to this type of cancer. The detection of HPV was analyzed in 47 penile squamous cell carcinoma samples. HPV DNA was detected in 48.9% of penile squamous cell carcinoma cases. High-risk HPV were present in 42.5% of cases and low-risk HPV were detected in 10.6% of penile squamous cell carcinomas. The RaSH approach identified differential expression of Annexin A1 (ANXA1), p16, RPL6, PBEF1 and KIAA1033 in high-risk HPV positive penile carcinoma; ANXA1 and p16 were overexpressed in penile squamous cells positive for high-risk HPVs compared to normal penile samples by qPCR. ANXA1 and p16 proteins were significantly more expressed in the cells from high-risk HPV-positive penile carcinoma as compared to HPV-negative tumors (p<0.0001) independently of the subtype of the carcinoma. Overexpression of ANXA1 might be mediated by HPV E6 in penile squamous cell carcinoma of patients with high-risk HPVs, suggesting that this gene plays an important role in penile cancer.

Mechanisms of virus immune evasion lead to development from chronic inflammation to cancer formation associated with human papillomavirus infection

Human papillomavirus (HPV) has developed strategies to escape eradication by innate and adaptive immunity. Immune response evasion has been considered an important aspect of HPV persistence, which is the main contributing factor leading to HPV-related cancers. HPV-induced cancers expressing viral oncogenes E6 and E7 are potentially recognized by the immune system. The major histocompatibility complex (MHC) class I molecules are patrolled by natural killer cells and CD8+ cytotoxic T lymphocytes, respectively. This system of recognition is a main target for the strategies of immune evasion deployed by viruses. The viral immune evasion proteins constitute useful tools to block defined stages of the MHC class I presentation pathway, and in this way HPV avoids the host immune response. The long latency period from initial infection to persistence signifies that HPV evolves mechanisms to escape the immune response. It has now been established that there are oncogenic mechanisms by which E7 binds to and degrades tumor suppressor Rb, while E6 binds to and inactivates tumor suppressor p53. Therefore, interaction of p53 and pRb proteins can give rise to an increased immortalization and genomic instability. Overexpression of NF-κB in cervical and penile cancers suggests that NF-κB activation is a key modulator in driving chronic inflammation to cancer. HPV oncogene-mediated suppression of NF-κB activity contributes to HPV escape from the immune system. This review focuses on the diverse mechanisms of the virus immune evasion with HPV that leads to chronic inflammation and cancer.

Human papillomavirus infection induces NF-κB activation in cervical cancer: A comparison with penile cancer

This study aimed to determine the relationship between human papillomavirus (HPV) and nuclear factor-κB (NF-κB) in cervical cancer using 62 tissues of cervical cancer, and to compare the findings to penile cancer. HPV-DNA integration is a crucial factor for malignant transformation in cervical cancer and can be identified using in situ hybridization. Of the 62 cases, HPV infection was detected in 28 (45.2%). This frequency was lower than in penile cancer (68.2%) as shown by our previous study. The earliest age of onset of cervical and penile cancer was 18 and 35, respectively, whereas the mean age of the initial diagnosis of cervical and penile cancer was 50.1 and 59.6, respectively. The discrepancies of HPV prevalence, earliest ages of onset and mean ages between cervical and penile cancer patients may result from the gender-based synergistic action of HPV associated with multiple epidemiological co-factors. Of the 28 HPV-infected cases, NF-κB expression was observed in the nucleus in 18 (64.3%), in the cytoplasm in 19 (67.9%) and in the nucleus and/or cytoplasm in 27 cases (96.4%). The overexpression of NF-κB in cervical cancer cases suggests that NF-κB activation is a key modulator in driving chronic inflammation to cancer.

Relationship among human papillomavirus infection, p16(INK4a), p53 and NF-κB activation in penile cancer from northern Thailand

Human papillomavirus (HPV) E6 and E7 oncoproteins are essential factors for HPV oncogenesis. These E6 and E7 gene products play a central role in the induction of malignant transformation by interacting with several cellular regulatory proteins such as p16(INK4a), p53 and nuclear factor κB (NF-κB). In the present study, conducted in northern Thailand, HPV-DNA was detected in penile cancer cases using an in situ hybridization procedure and p16(INK4a), p53 and NF-κB were detected by immunohistochemistry. Using the cell cycle regulatory proteins p16(INK4a) (61.5%) and p53 (71.8%), it was found that of the 51 cases, 39 (76.5%) were HPV-DNA-positive in penile cancer. On the other hand, 25% p16(INK4a) and 75% p53, respectively, were found in HPV-negative cases. Prevalence of HPV infection (76.5%) was shown in penile cancer cases in northern Thailand. No difference was found between HPV-positive and HPV-negative cases with respect to the presence of the cell cycle regulatory protein p53. On the other hand, p16(INK4a) was found to be different between HPV-positive and HPV-negative cases. Inactivation of tumor suppressor genes, such as p16(INK4a) and p53, to genetic instability, cell immortalization, accumulation of mutations and cancer formation, with or without HPV and irrespective of HPV infection, is therefore suggested. Of the 39 HPV-positive cases, 35 (89.7%) were NF-κB-positive in the nucleus, 29 (74.4%) in the cytoplasm and 37 (94.9%) in the nucleus and/or cytoplasm. NF-κB was detected in 4 (33.3%) of the 12 HPV-negative cases. Therefore, we propose that penile cancer cases with HPV infection are more likely to activate NF-κB than those without HPV infection.

Human papillomavirus genotypes in penile cancers from Japanese patients and HPV-induced NF-κB activation

The causal relationship between chronic inflammation and cancer is widely accepted. Numerous investigations have identified nuclear factor-κB (NF-κB) as an important modulator in driving chronic inflammation to cancer. This study aimed to determine the prevalence of human papillomavirus (HPV) in penile cancer in Japanese patients and whether NF-κB is subsequently overexpressed in penile cancer. Thirty-four specimens of penile tissue (16 malignant and 18 benign cases) were examined to determine the association of HPV infection. An in situ hybridization (ISH) method was used to detect and localize HPV-DNA. A sensitive HPV polymerase chain reaction (PCR) procedure was used for the detection of HPV-DNA, and DNA sequencing was used to identify the HPV genotype. HPV-DNA was detected in 37.5 and 75% of cases of penile cancer, using ISH and PCR, respectively. Our efforts to detect HPV genotypes were unsuccessful as HPV-DNA could not be extracted from these materials. Using ISH, a prevalence of 68.2% of HPV infection was found in penile cancer in Kenyan patients in east Africa. In the present study, all 9 HPV-positive cases, (100%) were NF-κB-positive in the nucleus and/or cytoplasm. In contrast, of the 25 HPV-negative cases, 15 (60%) were NF-κB-positive in the nucleus and/or cytoplasm. Therefore, ISH is a method which is able to prove infection of a large quantity of HPV more effectively when compared with PCR. Thus, a large quantity of HPV infection leads to the activity of NF-κB. The most prevalent genotype was the HPV-22 found in 83.3% of the penile cancer cases. In addition, HPV-11 was found in 81.8% of the non-cancer cases. For cases with a high level of infection, the activity of NF-κB increased compared with those with a low level of HPV infection.