Detection of the human papillomavirus and analysis of the TP53 polymorphism of exon 4 at codon 72 in penile squamous cell carcinomas

Genetic Predisposition to Persistent Human Papillomavirus-Infection and Virus-Induced Cancers

Human papillomaviruses (HPVs) are the most common sexually transmitted pathogens worldwide and among the more than 200 identified HPV types, approximately 15 high risk (HR-HPV) types are oncogenic, being strongly associated with the development of cervical cancer, anogenital cancers and an increasing fraction of head and neck squamous cell carcinomas (HNSCC). HPV-associated cervix cancer accounts for 83% of HPV-attributable cancers, and more than two-thirds of those cases occur in developing countries. Despite the high frequency of HPV infections, in most cases, the virus is cleared by the host immune response and only a small proportion of infected individuals develop persistent infections that can result in malignant transformation, indicating that other elements, including biological, genetic and environmental factors may influence the individual susceptibility to HPV-associated cancers. Previous studies have quantified that heritability, in the form of genetic variants, common in the general population, is implicated in nearly 30% of cervical cancers and a large number of studies conducted across various populations have identified genetic variants that appear to be associated with genes that predispose or protect the host to HPV infections thereby affecting individual susceptibility to HPV-associated cancers. In this article, we provide an overview of gene association studies on HPV-associated cancers with emphasis on genome-wide association study (GWAS) that have identified novel genetic factors linked to HPV infection or HPV-associated cancers.

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.

P53 Codon 72 Polymorphism and Risk for Squamous Cell Carcinoma of the Penis: A Caucasian Case-Control Study

Squamous cell carcinoma of the penis is a rare but often aggressive disease. A large proportion of penile cancers are associated with HPV infection, mainly with HPV high-risk subtypes 16 and 18. From other HPV-related malignancies a link between a functional SNP in the p53 gene (rs1042522, p.Arg72Pro) and a higher disease risk in the presence of HPV is documented. The p53 p.Arg72 variant was described as a risk factor for developing a malignancy in combination with the presence of HPV as the p.72Arg variant is more prone to HPV E6 protein-mediated degradation than the p.72Pro variant. For penile carcinoma there are only sparse data available on this topic. We therefore analyzed the distribution of this p53 codon 72 SNP in a cohort of 107 penile cancer patients and a healthy control group (n=194) using Restriction Fragment Length Polymorphism (RFLP) analysis. After DNA isolation a PCR amplicon including the variant nucleotide was generated. Based on the variant nucleotide this amplicon can be cleaved into two parts or remain unaffected by a restriction enzyme. Subsequent electrophoresis allowed the discrimination of SNP alleles in the investigated sample. Comparison of the allelic variants revealed no significant differences in the distribution of this SNP between cases and controls (p=0,622). There was also no difference in SNP distribution between cases with/without HPV infection (p=0,558) or histologic variants (p=0.339). In order to strengthen the impact of our data we performed a combined analysis of all published data on this topic with our results. This ended up in SNP distribution data from 177 cases and 1149 controls. Overall, there were also no significant differences in the allelic distribution of the p53 codon 72 SNP between either cases and controls (p=0,914) or HPV-positive and HPV-negative cases (p=0,486). From this most comprehensive data available to date we conclude that there is no influence of the p53 codon 72 SNP on the risk of development of penile carcinoma in Caucasians even in the presence of HPV.

Detection of Human Papillomavirus DNA, P53 and KI67 Expression in Penile Carcinomas

Our study is aimed at evaluating the presence of p53 and Ki67 expression by immunohistochemistry in a series of 11 paraffin-embedded penile carcinomas. We also investigated the presence of Human Papillomavirus (HPV) DNA in these tumours and performed an accurate typing by DNA sequencing on positive samples. Immunohistochemistry (IHC) was performed with the anti-p53 and Ki67 mouse monoclonal antibodies. DNA extracted from small sections of each specimen was submitted to amplification with HPV specific general primers; PCR products of the proper length were purified and sequenced. IHC demonstrated nuclear accumulation of mutated p53 and Ki 67 expression in 10/11 tumour samples (90.9%). The prevalence of HPV DNA was 72.7%; the most prevalent type was HPV16. Sequencing analysis revealed the presence of HPV53 (12.5%), HPV18 (25%) and HPV16 (62.5%). Out of the p53 or Ki67 positive carcinomas the percentage of HPV positives was 80% and 70% respectively. Our results indicate that penile carcinoma is frequently associated to high risk HPV and with diffuse p53 and Ki67 expression.

New cancer cases in France in 2015 attributable to infectious agents: a systematic review and meta-analysis

To provide an assessment of the burden of cancer in France in 2015 attributable to infectious agents. A systematic literature review in French representative cancer cases series was undertaken of the prevalence of infectious agents with the major associated cancer types. PubMed was searched for original studies published up to September 2016; random-effects meta-analyses were performed. Cancer incidence data were obtained from the French Cancer Registries Network, thereby allowing the calculation of national incidence estimates. The number of new cancer cases attributable to infectious agents was calculated using population-attributable fractions according to published methods. Of the 352,000 new cancer cases in France in 2015, 14,336 (4.1% of all new cancer cases) were attributable to infectious agents. The largest contributors were human papillomavirus (HPV) and Helicobacter pylori, responsible for 6333 and 4406 new cancer cases (1.8 and 1.3% of all new cancer cases) respectively. Infectious agents caused a non-negligible number of new cancer cases in France in 2015. Most of these cancers were preventable. The expansion of vaccination (i.e., for hepatitis B virus and HPV) and screen-and-treat programs (for HPV and hepatitis C virus, and possibly for H. pylori) could greatly reduce this cancer burden.

p53 Codon 72 Gene Polymorphism Studies and p53 Expression by Immunohistochemistry in Oral Lesions as Risk Factor for Malignancy

Background:

Wild-type p53 nuclear phosphoproteins are critical cell cycle regulatory tumor-suppressor gene. Genetic mutation of p53 gene is common in several head–neck cancers, usually associated with smoking and human papillomavirus (HPV) infection. In India, instead of HPV, tobacco/pan masala chewing is more commonly associated with oral cancer.

Aim:

The aim of this study was to investigate p53 codon 72 gene polymorphism and expression of p53 by immunohistochemistry (IHC) in oral lesions as a risk factor for its association with malignancy.

Materials and Methods:

A total of 41 cases of oral lesions comprising 6 cases of leukoplakia and 35 cases of oral squamous cell carcinoma (OSCC), between 30 and 60 years age and tobacco/pan masala chewers were taken. Molecular analysis of p53 codon 72 gene polymorphism was performed by polymerase chain reaction – restriction fragment length polymorphism for Arg/Arg, Arg/Pro, and Pro/Pro. Tissue expression of p53 was done by IHC.

Results:

Genotype frequencies of 35 carcinoma cases of p53 Arg/Arg, Arg/Pro, and Pro/Pro were 23%, 57%, and 20%, respectively, and six leukoplakia cases of p53 Arg/Arg and Arg/Pro genotype were 50% and 50%, respectively. By IHC for expression of p53 out of 35 cases of OSCC biopsies, 17 (48.57%) had weak staining, 14 cases (40%) showed evidence of p53 protein staining, and four cases (11.42%) showed negative staining. Among six cases of leukoplakia, 3 (50%) showed weak staining and 3 (50%) showed negative results.

Conclusion:

The findings of the study indicate that there is no significant association between p53 codon 72 gene polymorphism with OSCC and leukoplakia associated with tobacco/pan masala chewing.

Seroprevalence of Cutaneous Human Papillomaviruses and the Risk of External Genital Lesions in Men: A Nested Case-Control Study

Background

A variety of cutaneous human papillomaviruses (HPV) are detectable in genital epithelial lesions in men and non-melanoma skin cancer patients. It remains unclear whether these viruses are associated causally with skin lesions. To date, no study has prospectively examined the association between cutaneous HPV seropositivity and development of external genital lesions (EGLs) in men.

Objectives

To examine the association between seropositivity to cutaneous HPV types and the risk of subsequent development of EGLs.

Methods

A nested case-control study including 163 incident EGL cases and 352 EGL-free controls in the HPV Infection in Men (HIM) Study cohort was conducted. Cases were ascertained at each of up to 10 biannual clinical visits and verified through biopsy and pathological diagnoses. EGLs were categorized as condyloma, suggestive of condyloma, penile intraepithelial neoplasia (PeIN), and other EGLs. Archived serum specimens collected at baseline were tested for antibodies against 14 cutaneous HPV types (β types (5, 8, 12, 14, 17, 22, 23, 24, 38, and 47), α type 27, γ type 4, μ type 1, and ν type 41) using a GST L1-based multiplex serology assay. Socio-demographic and sexual behavior data were collected through a questionnaire. Using logistic regression, adjusted odds ratios (AOR) and 95% confidence intervals (CI) were estimated.

Results

Overall, seropositivity to ≥1 cutaneous HPV type (any-HPV) and ≥1 β types (any-β) was 58.3% and 37.5% among other EGL cases, 71.6% and 46.8% among condyloma, 66.8% and 50.0% among PeIN, and 71.9% and 38.4% among controls, respectively. Type-specific seropositivity was most common for ɤ-HPV 4, μ-HPV 1, and β-HPV 8. No statistically significant association was observed between any-HPV, any-β, and type-specific HPV seropositivity and subsequent development of EGLs across all pathological diagnoses.

Conclusions

Overall, seropositivity to cutaneous HPV was common among men; however, it appears that cutaneous HPV is not associated with the development of genital lesions in men.

Cutaneous beta human papillomaviruses and the development of male external genital lesions: A case-control study nested within the HIM Study

BACKGROUND

Cutaneous human papillomaviruses (HPVs) increase the risk of non-melanoma skin cancer in sun-exposed skin. We examined the role of beta-HPV in the development of male external genital lesions (EGLs), a sun-unexposed site.

METHODS

In this nested case-control study (67 men with pathologically-confirmed EGLs and 134 controls), exfoliated cells collected from the surface of lesions and normal genital skin 0, 6, and 12 months preceding EGL development were tested for beta-HPV DNA using a type-specific multiplex genotyping assay. Beta-HPV prevalence was estimated and conditional logistic regression was used to evaluate the association with condyloma, the most common EGL.

RESULTS

While beta-HPV prevalence among controls remained stable, the prevalence among cases was lowest on the surface of lesion. Detecting beta-HPV on the normal genital skin was not associated with the presence or development of condyloma.

CONCLUSIONS

Cutaneous beta-HPV does not appear to be contributing to pathogenesis in male genital skin.

Searching beyond the usual papillomavirus suspects in squamous carcinomas of the vulva, penis and head and neck

Human Papillomaviruses (HPVs) are involved in the etiology of anogenital and head and neck cancers. The HPV DNA prevalence greatly differs by anatomical site. Indeed, the high rates of viral DNA prevalence in anal and cervical carcinomas contrast with the lower fraction of cancer cases attributable to HPVs in other anatomical sites, chiefly the vulva, the penis and head and neck. Here we analyzed 2635 Formalin Fixed Paraffin Embedded surgical samples that had previously tested negative for the presence of HPVs DNA using the SPF10/DEIA procedure, in order to identify the presence of other PVs not explicitly targeted by standard molecular epidemiologic approaches. All samples were reanalyzed using five broad-PV PCR primer sets (CP1/2, FAP6064/FAP64, SKF/SKR, MY9/MY11, MFI/MFII) targeting the main PV main clades. In head and neck carcinoma samples (n=1141), we recovered DNA from two BetaHPVs, namely HPV20 and HPV21, and from three cutaneous AlphaPVs, namely HPV2, HPV57 and HPV61. In vulvar squamous cell carcinoma samples (n=902), we found one of the samples containing DNA of one cutaneous HPV, namely HPV2, and 29 samples contained DNA from essentially mucosal HPVs. In penile squamous cell carcinoma samples (n=592), we retrieved the DNA of HPV16 in 16 samples. Our results show first that the SPF10/DEIA is very sensitive, as we recovered only 2.1% (55/2635) false negative results; second, that although the DNA of cutaneous HPVs can be detected in cancer samples, their relative contribution remains anyway minor (0.23%; 6/2635) and may be neglected for screening and vaccination purposes; and third, their contribution to malignancy is not necessarily warranted and needs to be elucidated.

Establishment and characterization of a penile cancer cell line, penl1, with a deleterious TP53 mutation as a paradigm of HPV-negative penile carcinogenesis

PURPOSE

To establish penile cancer (PeCa) cell lines for the study of molecular mechanisms of carcinogenesis and testing therapeutic reagents.

MATERIALS AND METHODS

We successfully established two PeCa cell lines from fresh tumor tissues from 21 cases. One cell line named Penl1 was isolated from a lymph node metastasis (LNM) of penile squamous cell carcinoma (PeSCC), usual type and comprehensively characterized here. Our in-depth characterization analysis of the Penl1 cell line included morphology, tumorigenicity, genetic characteristics, protein expression, biology, and chemosensitivity. Penl1 was authenticated by single tandem repeat (STR) DNA typing.

RESULTS

Comparative histomorphology, genetic characteristics, and protein expression patterns revealed essential similarities between the cell line and its corresponding LNM. In-depth characterization analysis of Penl1 cell line revealed tumorigenicity in immunodeficient mice, negative human papilloma virus (HPV) and mycoplasma infection, TP53 mutations and sensitivity to cisplatin and epirubicin. STR DNA typing did not match any cell lines within three international cell banks. The limitation of this study is that one patient cannot represent the complete heterogeneity of PeCa, especially primary tumor.

CONCLUSIONS

We established and characterized an HPV-negative and moderately differentiated PeCa cell model with a TP53 missense mutation from a PeSCC, usual type patient. A preliminarily study of carcinogenesis and chemosensitivity suggests that this cell model carries a tumor suppressor gene mutation and is sensitive to chemotherapy drugs.

P53 gene codon 72 polymorphism in patients with oral squamous cell carcinoma in the population of northern Iran

Objectives: Squamous cell carcinoma is the most common cancer of the oral cavity, and several etiologic factors are involved in its development. Single nucleotide polymorphism (SNP) of the P53 gene codon 72 (P53c72) changes the structure of the protein and affects its activity. The prevalence of P53c72 different genotypes, which seems to vary with race and geographic location, has shown a strong correlation with many types of human cancers. The aim of this study was to investigate the correlation between P53c72 polymorphism and risk of oral squamous cell carcinoma (OSCC) in the heavily populated Gilan Province in northern Iran. Design of Study: This case-control study was done on 55 paraffin-embedded samples from OSCC patients and 100 samples of non-dysplastic oral cavity lesions. The P53c72 genotypes were determined using the ARMS-PCR method. SPSS-15 software was used for statistical analysis. Results: There were no significant statistical differences found between the prevalence of different P53c72 genotypes in the OSCC group vs. the control. However, the Pro/Pro genotype in OSCC samples showed a strong correlation with age, as 70% of such patients were below 50 years old. Interestingly, a large portion (40%) of the patients with the Pro/Pro genotype had the tumor in the lip area. Conclusions: Although P53c72 polymorphism does not appear to be a predisposing factor for OSCC in the population of Northern Iran, the Pro/Pro genotype could be considered as a risk factor for OSCC in adults below 50 years old and the anatomical location of the tumor.

Key words:OSCC, P53 codon 72 polymorphism, northern Iran.

Implications for human papillomavirus in penile cancer

Human papillomavirus infection (HPV) has been implicated in penile cancer, and although the annual incidence is estimated to be 1,570 in the United States, there are areas of the world in which the incidence is as much as 20-fold higher. Ample data in the literature support testing and vaccination against HPV-related cervical cancer, but for men and penile cancer, these data are lacking. However, some preliminary data would suggest that HPV not only plays an important role in a significant subset of patients with penile cancer but also may be a target for penile cancer prevention as well via initiation of a vaccination program in high-risk male populations.

Cutaneous human papillomavirus types detected on the surface of male external genital lesions: a case series within the HPV Infection in Men Study

BACKGROUND

Cutaneous human papillomaviruses (HPVs) may be associated with cutaneous epithelial lesions and non-melanoma skin cancers. No study has systematically evaluated the presence of genus beta [β]-HPV in male genital skin or external genital lesions (EGLs)

OBJECTIVES

To examine cutaneous β-HPV types detected on the surface of EGLs in men and describe their presence prior to EGL development.

STUDY DESIGN

A retrospective case series was conducted among 69 men with pathologically confirmed EGLs (n=72) who participated in the HPV Infection in Men Study. Archived exfoliated cells collected from the surface of each EGL and normal genital skin specimens 6-12 months preceding EGL development were tested for β-HPV DNA using a type-specific multiplex genotyping assay.

RESULTS

β-HPV DNA was detected on 61.1% of all EGLs, with types 38 (16.7%), 5 (15.3%), and 12 (12.5%) most commonly identified. HPV prevalence differed across pathological diagnoses, with the largest number of β-HPV types detected on condylomas. Most β-HPV types were detected on normal genital skin prior to EGL development, though the prevalence was lower on EGLs compared to preceding normal genital skin.

CONCLUSIONS

EGLs and the normal genital skin of men harbor a large number of β-HPV types; however, it appears that β-HPVs are unrelated to EGL development in men. Despite evidence to support a causal role in skin carcinogenesis at UVR-exposed sites, cutaneous HPV appears unlikely to cause disease at the UVR-unexposed genitals.

Northwestern China: a place to learn more on oesophageal cancer. Part two: gene alterations and polymorphisms

In the first part of this review, some behavioural and environmental risk factors playing important roles in the development of Kazakh's oesophageal squamous cell carcinoma (OSCC) were presented. Although all individuals have been exposed to the same environment and share the same behaviour, some of them will not develop OSCC. Thus, gene susceptibility and/or gene polymorphism are unavoidably involved. The molecular events underlying the initiation and progression of OSCC remain, however, poorly understood. In the second part of our review of OSCC in northwestern China, especially in the high-risk Kazakh population, some recent progress in the study of the molecular biology underlying oesophageal carcinogenesis, including chromosome deletions and loss of heterozygocity, polymorphisms of genes involved in xenobiotic metabolizing and DNA repair, and genetic alterations of transcriptional factors and apoptosis genes are presented. Results obtained in this high-risk population are compared with those obtained in other areas that are also known to be at high risk for OSCC, and whenever possible, with those studies performed in European, American or Australian low-risk areas. Recent advances in the investigation of the proteomics and microRNA biomarkers potentially useful for an earlier diagnosis and/or prognosis of OSCC are also discussed.

Genital HPV infection and related lesions in men

Human papillomavirus (HPV) is highly prevalent in men and there is an interest in further understanding the relationship between HPV infection and disease in men, including the development of genital warts, penile intraepithelial neoplasia and invasive penile carcinomas. Genital warts are caused by HPV 6/11 and are the most common clinical manifestation of HPV in men. Though they are benign and not associated with mortality, they are a source of psychosocial distress and physical discomfort. HPV infection can also develop into invasive penile carcinoma which is associated with morbidity and mortality. Approximately 40% of invasive penile carcinomas are attributable to HPV with HPV 16, 18, and 6/11 being the genotypes most commonly detected in penile tumors. Penile carcinomas of the basaloid and warty histologic subtypes are most likely to test positive for HPV. In addition to HPV infection, the risk factors most strongly associated with penile cancer are lack of neonatal circumcision, phimosis (the inability of uncircumcised men to fully retract the foreskin), and anogenital warts. Male vaccination with the quadrivalent HPV vaccine that protects against HPV 6/11/16/18 has been shown to significantly reduce HPV-associated anogenital infection and disease in men. If the quadrivalent vaccine is successfully disseminated to large segments of the young male population, there is the potential for substantial reduction in genital HPV infection and related lesions in men.

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.

Systematic review of human papillomavirus prevalence in invasive penile cancer

OBJECTIVE

Type-specific prevalence data of human papillomavirus (HPV) DNA in penile carcinoma are needed to determine the potential impact of HPV prophylactic vaccines, assuming demonstrated efficacy in men.

METHODS

A review was conducted using search terms including HPV and penile cancer. Studies using polymerase chain reaction (PCR) assays for HPV DNA detection in invasive penile carcinoma were included.

RESULTS

A total of 1,266 squamous cell carcinoma (SCC) cases contributed data from 30 studies. The number of SCC was similar in Europe (28.2%), North America (27.6%), South America (23.9%) and Asia (20.4%). All SCC were histologically confirmed with biopsies for DNA detection. Most commonly used PCR primers were type-specific (35.2%), and combination PCR (18.2%). HPV prevalence was 47.9%, ranging from 22.4% in verrucous SCC to 66.3% for the basaloid/warty subtypes. HPV16 (30.8%), HPV6 (6.7%) and HPV18 (6.6%) were the most prevalent types. HPV16 and/or HPV 18 prevalence was 36.7%.

CONCLUSIONS

HPV DNA was detected in half of SCC, with HPV16 being the most common type. If proven efficacious in men, prophylactic vaccines targeting carcinogenic types HPV16 and 18 could potentially reduce approximately one-third of incident SCC.

Molecular prognostic factors in penile cancer

OBJECTIVES

Penile cancer is a rare tumour in developed countries but more common in South America and East Africa. Although pathological prognostic factors have been established, there is great interest in evaluating molecular markers which correlate with prognosis and outcome.

METHODS

We have reviewed the current status of our understanding of the molecular biology of penile cancer in order to identify established and potential prognostic factors in penile cancer. We have conducted an extensive literature search to review the current understanding of the role of prognostic markers in penile cancer.

RESULTS

Although several markers have been evaluated, currently the clinical application of these markers is limited. HPV positive tumours show a variable prognostic outcome. P53 status may correlate with survival in T1 disease but further studies are required to establish the link to lymph node spread.

CONCLUSIONS

Pathological variables are well-established but further work is required to investigate the role of molecular markers. The development of molecular prognostic markers is important for the surveillance of patients and prediction of lymph node involvement as well as a prognostic marker for survival.

Screening of microsatellite markers in penile cancer reveals differences between metastatic and nonmetastatic carcinomas

Penile cancer, observed only rarely in the western world, represents a carcinoma that may be cured by resection of primary lesion and in case of lymph node metastasis by early lymph node dissection. This early inguinal lymphadenectomy bares a significant better survival even in cases of nonpalpable lymph nodes, but carries also a high risk of overtreatment, especially in lower tumor stages. Due to the low incidence, only few data are available on the molecular genetic background of this tumor, especially concerning tumor progression and metastasis. Therefore, we studied 62 microsatellite markers in 28 penile carcinomas searching for markers predicting progression or outcome. LOH in more than 25% of primary tumors was found on six different chromosomes, including 2q, 6p, 8q, 9p, 12q and 17p13. Statistically significant correlations could be established in D6S260 to clinical outcome and in markers from chromosomes 6, 9 and 12 to tumor stage and metastasis. These regions are worthy for further analysis concerning tumor suppressor genes and metastasis suppressor genes.

Molecular and genetic pathways in penile cancer

Penile cancer is a rare malignancy affecting more than 400 men per year in the UK. Studies on the aetiopathogenesis of this cancer have focused on its association with the human papilloma virus; however, there have also been several studies on the genetic and molecular changes that occur. Human papilloma virus has shown differential levels of prevalence in association with different types of penile cancer. The virus seems to act as a trigger for this disease via its oncogenes. We review this process, and assess the independent genetic events that occur in penile cancer. Knowledge of this cancer is progressing slowly and could be furthered by multicentre cooperation and the formation of national tumour banks, which will aid the development of novel therapeutic agents to reduce the morbidity and mortality of penile cancer.

p53 codon 72 polymorphism in basal cell carcinoma of the skin

Basal cell carcinoma (BCC) is the most prevalent cancer in Iran. A common polymorphism at codon 72 of exon 4 of p53 tumor suppressor gene has been reported to be associated with increased inheritable susceptibility to several cancers. In the present study the frequency of p53 codon 72 polymorphism in 91 patients with BCC of skin, compared to 465 healthy normal individuals, was investigated. In total, there was no significant difference in the p53 genotypes between patients and controls. However, there was an apparent increase in the Arg/Arg genotype among those BCC patients who had a history of occupational sun exposure, compared to non-exposed patients (46.3% vs. 23.1%, P=0.11). A trend of increase in the frequency of Arg allele among sun-exposed patients was also observed (69.4% vs. 53.8%, P=0.07). Comparison of the genotype frequencies between sunexposed patients and normal controls confirmed the accumulation of Arg/Arg genotype in these patients (46.3% vs. 34.8%, P = 0.07). In addition, the frequency of Arg allele was significantly higher in sunexposed patients compared to controls (69.4% vs. 58.2%, P=0.03). Our results suggest that Arg allele at codon 72 of p53 gene might affect the risk of ultraviolet-induced basal cell carcinoma.

p53 polymorphism in human papillomavirus-associated Kazakh’s esophageal cancer in Xinjiang, China

AIM: To investigate the relationship between p53 codon 72 polymorphism and human papillomavirus (HPV) type 16 infection in Kazakh’s esophageal cancer (EC) in Xinjiang, China.

METHODS: Encoding regions of p53 codon 72 and HPV-16 E6 were amplified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and polymerase chain reaction (PCR) methods using pairs of primary esophageal squamous cell carcinoma (SCC) tissue and corresponding normal mucosa, which were collected from 104 patients of Kazakh in Xinjiang, China.

RESULTS: Only arginine allele was detected in 70.1% (39/55) of HPV-16-E6- positive cases but only in 40.8% (20/49) of HPV-16-E6-negative cases (P < 0.05; OR, 3.53; 95%CI, 1.57-7.98). In contrast, such a significant correlation between p53 polymorphism and HPV infection was not evident in corresponding normal mucosae. The allele frequency of Arg allele in cancer cases (0.68) was higher than that in normal mucosa samples (0.54) (P < 0.05; OR, 1.80; 95%CI, 1.21-2.69).

CONCLUSION: p53 codon 72 Arg homozygous genotype is one of the high-risk genetic factors for HPV-associated SCC of Kazakh. Individuals carrying Arg allele compared to those with Pro allele have an increased risk for esophageal SCC.