Geographic heterogeneity in the prevalence of human papillomavirus in head and neck cancer

Human papillomavirus (HPV) causes oropharyngeal squamous cell carcinoma (OPSCC), although strongly divergent results have been reported regarding the prevalence of HPV16 in different countries, whether this represents important differences in etiology remains unclear. Applying rigorous protocols for sample processing, we centrally evaluated 1,420 head and neck tumors (533 oropharynx, 395 oral cavity and 482 larynx) from studies conducted in the US, Europe and Brazil for mucosal HPV DNA and p16^INK4a expression to evaluate regional heterogeneity in the proportion of HPV16‐associated OPSCC and other head and neck cancer, and to assess covariates associated with the risk of HPV16‐positive OPSCC. While majority of OPSCC in the US (60%) were HPV16‐positive, this proportion was 31% in Europe and only 4% in Brazil (p < 0.01). Similar differences were observed for other head and neck tumors, ranging from 7% in the US and 5% in Europe, to 0% in South America. The odds of HPV16‐positive OPSCC declined with increasing pack years of smoking (OR: 0.75; 95% CI: 0.64–0.87) and drink years of alcohol use (OR: 0.64; 95% CI: 0.54–0.76). These results suggest that while the contribution of HPV16 is substantial for the oropharynx, it remains limited for oral cavity and laryngeal cancers.     

P16INK4A immunostaining is a strong indicator for high‐risk‐HPV‐associated oropharyngeal carcinomas and dysplasias,but is unreliable to predict low‐risk‐HPV‐infection in head and neck papillomas and laryngeal dysplasias

Human papillomavirus (HPV) is a risk factor for the development of benign and malignant mucosal head and neck lesions. P16^INK4A is often used as a surrogate marker for HPV‐infection, although there is still controversy with respect its reliability. Our aim was to determine if p16^INK4A overexpression can accurately predict both high‐risk and low‐risk‐HPV‐presence in (pre)malignant and benign head and neck lesions. P16^INK4A immunohistochemistry was performed on paraffin‐embedded tissue sections of 162 oropharyngeal squamous cell carcinomas (OPSCC), 14 tonsillar and 23 laryngeal dysplasias, and 20 tonsillar and 27 laryngeal papillomas. PCR, enzyme‐immunoassay and FISH analysis were used to assess HPV‐presence and type. Of the 162 OPSCC and 14 tonsillar dysplasias, 51 (31%) and 10 (71%) were HPV16‐positive, respectively. All tonsillar papillomas were HPV‐negative and four laryngeal dysplasias and 26 laryngeal papillomas were positive for HPV6 or ?11. P16^INK4A immunohistochemistry revealed a strong nuclear and cytoplasmic staining in 50 out of 51 HPV16‐positive and 5 out of 111 HPV‐negative OPSCC (p < 0.0001) and in all HPV16‐positive tonsillar dysplasias, whereas highly variable staining patterns were detected in the papillomas and laryngeal dysplasias, irrespective of the HPV‐status. In addition, the latter lesions generally showed a higher nuclear than cytoplasmic p16^INK4A immunostaining intensity. In conclusion, our data show that strong nuclear and cytoplasmic p16^INK4A overexpression is a reliable surrogate indicator for HPV16 in OPSCC and (adjacent) dysplasias. For HPV6 or ?11‐positive and HPV‐negative benign and premalignant lesions of the tonsil and larynx, however, p16^INK4A immunostaining is highly variable and cannot be recommended to predict HPV‐presence.     

Time trends in the prevalence of HPV in oropharyngeal squamous cell carcinomas in northern Spain (1990–2009)

Recent studies support an important role for human papillomavirus (HPV) in oropharyngeal squamous cell carcinomas (OPSCC), although the incidence varies widely depending on the geographic location and time period studied. The aim of this study was to determine the proportion of HPV in a large cohort of OPSCC in northern Spain in the years 1990–2009. Clinical records and paraffin embedded tumor specimens of 248 consecutive patients surgically treated for OPSCC (140 tonsillar and 108 base of tongue) between 1990 and 2009 were retrieved. OPSCC cases were histomorphologically evaluated, and protein expression of p16 and p53 was analyzed by immunohistochemistry. Detection of high‐risk HPV DNA was performed by GP5+/6+‐PCR and in situ hybridization (ISH). Thirty cases (12%) were positive for p16 immunostaining, of which eight (3.2% of the total series) were found positive for HPV type 16 by genotyping of GP5+6+‐PCR products. All HPV GP5+/6+‐PCR‐positive tumors were p53‐immunonegative, seven had a basaloid morphology and seven were also positive by HPV ISH. Presence of HPV correlated inversely with tobacco and alcohol consumption (p < 0.001), but not with age of onset of OPSCC. Overall survival was better in the HPV‐positive group, although not statistically significant (p = 0.175). OPSCC patients in northern Spain demonstrated a low involvement of HPV, increasing (although not significantly, p = 0.120) from 1.8% in 1990–1999 to 6.1% of cases in 2000–2009.     

Molecular characterization of p16‐immunopositive but HPV DNA‐negative oropharyngeal carcinomas

Recent studies have reported that p16 protein overexpression qualifies as a surrogate marker identifying an oncogenic human papillomavirus (HPV) infection in oropharyngeal squamous cell carcinoma (OPSCC). However, there is still a percentage of OPSCCs that are positive for p16 immunohistochemistry (p16 IHC) but lack HPV DNA. The objective of this study was to characterize this group at the molecular level by performing sensitive HPV DNA‐ and RNA‐based PCR methods and genetic profiling. All patients diagnosed with an OPSCC in the period 2000–2006 in two Dutch university medical centers were included (n = 841). The presence of HPV in a tumor sample was tested by p16 IHC followed by an HPV DNA GP5+/6+ PCR. p16 IHC scored positive in 195 samples, of which 161 were HPV DNA‐positive and 34 (17%) HPV DNA‐negative. In the latter group, a SPF₁₀‐LiPA25 assay, an HPV16 type‐specific E7 PCR and an E6 mRNA RT‐PCR were performed. Next, ten of these cases were further analyzed for loss of heterozygosity (LOH) of 15 microsatellite markers at chromosome arms 3p, 9p and 17p. Of the 34 p16‐positive but PCR‐negative OPSCCs, two samples tested positive by SPF₁₀ assay, HPV16 E7 PCR and HPV16 E6 mRNA RT‐PCR. Three samples tested positive by SPF₁₀ assay but negative by the HPV16‐specific assays. Nine of ten cases that were tested for LOH showed a genetic pattern comparable to that of HPV‐negative tumors. This study categorizes p16‐positive but HPV DNA‐negative OPSCCs as HPV‐negative tumors based on genetic profiling. This study highlights the importance of performing HPV testing in addition to p16 IHC for proper identification of HPV‐associated OPSCCs.     

Combined P16 and human papillomavirus testing predicts head and neck cancer survival

While its prognostic significance remains unclear, p16^INK4a protein expression is increasingly being used as a surrogate marker for oncogenic human papillomavirus (HPV) infection in head and neck squamous cell carcinomas (HNSCC). To evaluate the prognostic utility of p16 expression in HNSCC, we prospectively collected 163 primary tumor specimens from histologically confirmed HNSCC patients who were followed for up to 9.4 years. Formalin fixed tumor specimens were tested for p16 protein expression by immunohistochemistry (IHC). HPV type‐16 DNA and RNA was detected by MY09/11‐PCR and E6/E7 RT‐PCR on matched frozen tissue, respectively. P16 protein expression was detected more often in oropharyngeal tumors (53%) as compared with laryngeal (24%), hypopharyngeal (8%) or oral cavity tumors (4%; p < 0.0001). With respect to prognosis, p16‐positive oropharyngeal tumors exhibited significantly better overall survival than p16‐negative tumors (log‐rank test p = 0.04), whereas no survival benefit was observed for nonoropharyngeal tumors. However, when both p16 and HPV DNA test results were considered, concordantly positive nonoropharyngeal tumors had significantly better disease‐specific survival than concordantly negative nonoropharyngeal tumors after controlling for sex, nodal stage, tumor size, tumor subsite, primary tumor site number, smoking and drinking [adjusted hazard ratio (HR) = 0.04, 0.01–0.54]. Compared with concordantly negative nonoropharyngeal HNSCC, p16(+)/HPV16(?) nonoropharyngeal HNSCC (n = 13, 7%) demonstrated no significant improvement in disease‐specific survival when HPV16 was detected by RNA (adjusted HR = 0.83, 0.22–3.17). Our findings show that p16 IHC alone has potential as a prognostic test for oropharyngeal cancer survival, but combined p16/HPV testing is necessary to identify HPV‐associated nonoropharyngeal HNSCC with better prognosis.     

No role for human papillomavirus in esophageal squamous cell carcinoma in China

Certain regions of China have high rates of esophageal squamous cell carcinoma (ESCC). Previous studies of human papillomavirus (HPV), a proposed causal factor, have produced highly variable results. We attempted to evaluate HPV and ESCC more definitively using extreme care to prevent DNA contamination. We collected tissue and serum in China from 272 histopathologically‐confirmed ESCC cases with rigorous attention to good molecular biology technique. We tested for HPV DNA in fresh‐frozen tumor tissue using PCR with PGMY L1 consensus primers and HPV16 and 18 type‐specific E6 and E7 primers, and in formalin‐fixed paraffin‐embedded tumor tissue using SPF₁₀ L1 primers. In HPV‐positive cases, we evaluated p16^INK4a overexpression and HPV E6/E7 seropositivity as evidence of carcinogenic HPV activity. β‐globin, and thus DNA, was adequate in 98.2% of the frozen tumor tissues (267/272). Of these, 99.6% (95% confidence interval (CI) = 97.9–100.0%) were negative for HPV DNA by PGMY, and 100% (95% CI = 98.6–100%) were negative by HPV16/18 E6/E7 PCR. In the corresponding formalin‐fixed paraffin‐embedded tumor specimens, 99.3% (95% CI = 97.3–99.9%) were HPV negative by SPF₁₀. By PGMY, 1 case tested weakly positive for HPV89, a noncancer causing HPV type. By SPF₁₀, 2 cases tested weakly positive: 1 for HPV16 and 1 for HPV31. No HPV DNA‐positive case had evidence of HPV oncogene activity as measured by p16^INK4a overexpression or E6/E7 seropositivity. This study provides the most definitive evidence to date that HPV is not involved in ESCC carcinogenesis in China. HPV DNA contamination cannot be ruled out as an explanation for high HPV prevalence in ESCC tissue studies with less stringent tissue procurement and processing protocols.     

Human papillomavirus DNA load and p16INK4a expression predict for local control in patients with anal squamous cell carcinoma treated with chemoradiotherapy

As the detection rate of HPV‐DNA in anal carcinoma commonly exceeds 90%, a comparison between sole HPV‐positive and HPV‐negative cancers with respect to treatment response following chemoradiotherapy (CRT) and long‐term oncological outcome is challenging. Against this background, we aimed to assess HPV types and HPV DNA load in formalin‐fixed paraffin‐embedded tissue (FFPE) of 95 patients treated with standard CRT for anal cancer to correlate viral load (≤/> median) with local failure, distant metastases, cancer‐specific (CSS) and overall survival (OS) rates. Various clinicopathologic parameters and the immunohistochemical marker p16^INK4a were evaluated for any correlation with HPV16 DNA load and were included in uni‐ and multivariate analyses. The overall prevalence of HPV DNA was 95.8% with HPV16 monoinfection being the most commonly encountered HPV type (78.9%), followed by HPV16 and 31, 35, 39, 44, 58, 66 and 81 dual infection in 9 patients (9.5%). HPV16 DNA load was significantly associated with p16^INK4a expression (p = 0.001). Patients with HPV16 DNA load ≤ median and low p16^INK4a expression showed significantly worse local control (HPV16 DNA load: univariate p = 0.023, multivariate p = 0.042; p16^INK4a: univariate p = 0.021), and OS (HPV16 DNA load: univariate p = 0.02, multivariate p = 0.03). Moreover, a combined HPV16 DNA load and p16^INK4a variable revealed a significant correlation to decreased local failure, and increased CSS and OS (p = 0.019, p = 0.04 and p = 0.031). In conclusion, these data indicate that HPV16 DNA load and p16^INK4a expression are significant prognostic factors for local tumor control and overall survival of patients with anal SCC following CRT.     

p16INK4a overexpression predicts translational active human papillomavirus infection in tonsillar cancer

The causal role of human papillomaviruses (HPV) in squamous cell carcinogenesis of tonsillar cancers (TSCC) depends on the activity of the viral oncoproteins E6 and E7, leading to inactivation of the cellular tumor suppressor p53 and the retinoblastoma gene product pRb. Because of the negative feedback mechanisms, the pRb inactivation causes an increase of the inhibitor of the cyclin‐dependent kinases p16^INK4a. In 39 TSCC specimens, genotyping based on the amplification of HPV DNA was carried out using PCR by applying HPV type‐specific oligonucleotides. Subsequently, amplicons were hybridised with fluorescence‐labeled complementary probes using the Southern blot technology. For HPV E6/E7 mRNA expression, Northern hybridization and RT‐PCR were performed, and for p16^INK4a detection, immunohistochemistry was performed. With 21/39 (53%) HPV‐positives, the detection rate is within the range that can be expected in TSCC. The E6/E7 oncogene mRNA was detectable in 11 cases, 10 of which showed positive signals after p16^INK4a staining. Albeit the small study group was investigated, the correlation of the HPV DNA status with the p16^INK4a expression was of statistical significance (p = 0.02). Kaplan‐Meier estimations revealed better survival outcome for patients with HPV‐positive tumors with detectable E6/E7 mRNA and p16^INK4a overexpression (p = 0.02, median observation time 29 months). As mRNA expression tests are not routinely available in many clinical diagnostic laboratories, and based on the high correlation of p16^INK4a staining with HPV E6/E7 mRNA expression, in conclusion we suggest for a deeper exploration for the use of p16^INK4a as a surrogate marker with the potential to impact the standard of care of HPV DNA‐positive head and neck carcinomas.     

Human papillomavirus DNA prevalence and type distribution in anal carcinomas worldwide

Knowledge about human papillomaviruses (HPV) types involved in anal cancers in some world regions is scanty. Here, we describe the HPV DNA prevalence and type distribution in a series of invasive anal cancers and anal intraepithelial neoplasias (AIN) grades 2/3 from 24 countries. We analyzed 43 AIN 2/3 cases and 496 anal cancers diagnosed from 1986 to 2011. After histopathological evaluation of formalin‐fixed paraffin‐embedded samples, HPV DNA detection and genotyping was performed using SPF‐10/DEIA/LiPA₂₅ system (version 1) . A subset of 116 cancers was further tested for p16^INK4a expression, a cellular surrogate marker for HPV‐associated transformation. Prevalence ratios were estimated using multivariate Poisson regression with robust variance in the anal cancer data set. HPV DNA was detected in 88.3% of anal cancers (95% confidence interval [CI]: 85.1–91.0%) and in 95.3% of AIN 2/3 (95% CI: 84.2–99.4%). Among cancers, the highest prevalence was observed in warty–basaloid subtype of squamous cell carcinomas, in younger patients and in North American geographical region. There were no statistically significant differences in prevalence by gender. HPV16 was the most frequent HPV type detected in both cancers (80.7%) and AIN 2/3 lesions (75.4%). HPV18 was the second most common type in invasive cancers (3.6%). p16^INK4a overexpression was found in 95% of HPV DNA‐positive anal cancers. In view of the results of HPV DNA and high proportion of p16^INK4a overexpression, infection by HPV is most likely to be a necessary cause for anal cancers in both men and women. The large contribution of HPV16 reinforces the potential impact of HPV vaccines in the prevention of these lesions.     

Mucosal alpha‐papillomaviruses are not associated with esophageal squamous cell carcinomas: Lack of mechanistic evidence from South Africa,China and Iran and from a world‐wide meta‐analysis

Epidemiological and mechanistic evidence on the causative role of human papillomaviruses (HPV) in esophageal squamous cell carcinoma (ESCC) is unclear. We retrieved alcohol‐ and formalin‐fixed paraffin‐embedded ESCC tissues from 133 patients seropositive for antibodies against HPV early proteins, from high‐incidence ESCC regions: South Africa, China and Iran. With rigorous care to prevent nucleic acid contamination, we analyzed these tissues for the presence of 51 mucosotropic human alpha‐papillomaviruses by two sensitive, broad‐spectrum genotyping methods, and for the markers of HPV‐transformed phenotype: (i) HPV16/18 viral loads by quantitative real‐time PCR, (ii) type‐specific viral mRNA by E6*I/E6 full‐length RT‐PCR assays and (iii) expression of cellular protein p16^INK4a. Of 118 analyzable ESCC tissues, 10 (8%) were positive for DNA of HPV types: 16 (4 tumors); 33, 35, 45 (1 tumor each); 11 (2 tumors) and 16, 70 double infection (1 tumor). Inconsistent HPV DNA+ findings by two genotyping methods and negativity in qPCR indicated very low viral loads. A single HPV16 DNA+ tumor additionally harbored HPV16 E6*I mRNA but was p16^INK4a negative (HPV16 E1 seropositive patient). Another HPV16 DNA+ tumor from an HPV16 E6 seropositive patient showed p16^INK4a upregulation but no HPV16 mRNA. In the tumor tissues of these serologically preselected ESCC patients, we did not find consistent presence of HPV DNA, HPV mRNA or p16^INK4a upregulation. These results were supported by a meta‐analysis of 14 other similar studies regarding HPV‐transformation of ESCC. Our study does not support the etiological role of the 51 analyzed mucosotropic HPV types in the ESCC carcinogenesis.     

Immunocytochemical colocalization of P16(INK4a) and Ki-67 predicts CIN2/3 and AIS/adenocarcinoma

BACKGROUND:

Although previous studies have shown that p16^INK4a and Ki‐67 are sensitive and specific markers for high‐grade lesions (≥CIN2) on cervical biopsies, limited information is available regarding the performance of a dual‐staining approach as a diagnostic adjunct in cervical cytology. We evaluated a dual p16^INK4a/Ki‐67 immunocytochemistry (ICC) assay to determine its sensitivity and specificity versus that of high‐risk HPV (HR‐HPV) in a US‐based pilot cytology study.

METHODS:

ThinPrep specimens from 122 cervical cytology specimens encompassing 23 negative (NILM), 20 ASC‐US, 22 LSIL, 17 ASCH, 22 HSIL, and 18 AGC cases were processed for multiplexed ICC staining using a CINtec Plus Kit. Dual‐positive assay results were defined based on the detection of 1 or more epithelial cells that were stained for both p16^INK4a and Ki‐67 without regard to cellular morphology. HR‐HPV testing was performed by multiplex PCR with capillary electrophoresis genotyping.

RESULTS:

Dual staining for p16^INK4a and Ki‐67 was frequently detected in HSIL and AGC but was rarely detected in NILM cases. The HR‐HPV assay showed a sensitivity of 76.2% and a specificity of 55.8% for the detection of clinically significant cervical squamous or endometrial lesions. In contrast, the colocalization of p16^INK4a plus Ki‐67 maintained a high sensitivity of 81.8% and improved specificity to 81.8% for biopsy‐confirmed CIN2/3, endocervical adenocarcinoma, or endometrial adenocarcinoma.

CONCLUSIONS:

Dual staining for p16^INK4a/Ki‐67 immunocytochemistry dramatically increased specificity and maintained high‐level sensitivity for the diagnosis of CIN2/3 or glandular lesions compared with PCR‐based testing for HR‐HPV. Cancer (Cancer Cytopathol) 2012. © 2011 American Cancer Society.     

p16INK4a is superior to high‐risk human papillomavirus testing in cervical cytology for the prediction of underlying high‐grade dysplasia

BACKGROUND

The primary goal of this study was to compare the clinical performance of an optimized and rigorously controlled immunocytochemical (ICC) assay for p16^INK4a to high‐risk (HR) human papillomavirus (HPV) detection by polymerase chain reaction (PCR) as diagnostic adjuncts for cytology specimens from colposcopy patients.

METHODS:

The study included 403 cervical cytology specimens collected within 3 months of colposcopy. The colposcopic impression and cervical biopsy diagnosis served as the standards for correlation with cytological, p16^INK4a, and HPV data. p16^INK4a was evaluated using an immunoperoxidase‐based assay that was linear over 4 logs for the detection of HeLa‐spiked positive control cytology specimens, using a threshold for positive test results that was based on receiver operating characteristic curve analysis. HR‐HPV was detected by multiplex PCR using genotype‐specific primers.

RESULTS:

In all combined diagnostic categories (negative for intraepithelial lesion and malignancy, atypical glandular cells, atypical squamous cells of undetermined significance, atypical squamous cells cannot exclude high‐grade squamous intraepithelial lesion, low‐grade squamous intraepithelial lesion, and high‐grade squamous intraepithelial lesion), the p16^INK4a ICC and HR‐HPV assays, respectively, had sensitivity of 81.7% and 83.3% (P = .81) and specificity of 78.1% and 50.9% (P < .001) for the detection of underlying ≥grade 2 cervical intraepithelial neoplasia (CIN) lesions on biopsy. Furthermore, the positive predictive value of p16^INK4a ICC was greater than that of HR‐HPV for patients with biopsies ≥CIN‐2 (41.2% and 24.2%, respectively, P = .001).

CONCLUSIONS:

This p16^INK4a immunocytochemical assay has superior specificity but similar sensitivity to HR‐HPV testing to predict underlying high‐grade dysplastic lesions in patients who are referred for colposcopy. The determination of the overall performance characteristics of p16^INK4a immunocytochemistry, as an independent test or in combination with HPV testing in low‐risk screening populations, however, will require subsequent large‐scale prospective clinical trials. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.     

p16INK4A immunohistochemical staining may be helpful in distinguishing branchial cleft cysts from cystic squamous cell carcinomas originating in the oropharynx

BACKGROUND:

We investigated p16^INK4A expression in branchial cleft cysts and its utility in distinguishing branchial cleft cysts from metastatic head and neck squamous cell carcinomas (SCCs) in fine‐needle aspiration biopsies (FNABs).

METHODS:

A study set comprising 41 resections (15 SCC and 26 branchial cleft cysts) and a test set of 15 FNABs (11 SCC and 4 branchial cleft cysts) were analyzed with p16^INK4A immunohistochemistry and human papillomavirus (HPV) polymerase chain reaction (PCR)/pyrosequencing. Cases with discrepant p16^INK4A and PCR/pyrosequencing results were further evaluated with HPV in situ hybridization (ISH). SCCs were divided into keratinizing SCC and nonkeratinizing SCC groups and site of origin.

RESULTS:

Metastatic oropharyngeal nonkeratinizing SCC in the study set exhibited diffuse, strong p16^INK4A (7 of 7) and HPV16 DNA positivity (6 of 6), while keratinizing SCC from the larynx and oral cavity was negative for p16^INK4A. p16^INK4A reactivity in the branchial cleft cyst study set was characterized by focal, strong staining (6 of 21) involving the superficial squamous epithelium. HPV DNA was identified in 7 of 19 branchial cleft cyst study set cases by PCR/pyrosequencing, but these cases were negative by HPV ISH. In the test set, oropharyngeal nonkeratinizing SCC exhibited diffuse, strong p16^INK4A (3 of 3) and HPV16 DNA (2 of 2), while metastatic keratinizing SCC was negative for p16^INK4A and HPV DNA. All 4 FNABs of branchial cleft cysts were negative for p16^INK4A. Diffuse, strong p16^INK4A correlated with oropharyngeal origin (P = .001) and nonkeratinizing morphology (P = .0001).

CONCLUSIONS:

Branchial cleft cysts can exhibit focal strong reactivity limited to the superficial squamous epithelium and glandular epithelium. Although p16^INK4A immunohistochemistry may be helpful in distinguishing oropharyngeal nonkeratinizing SCC from branchial cleft cysts in FNAB specimens, it is not helpful in cases of keratinizing SCC because these cases are typically negative for p16^INK4A. Cancer (Cancer Cytopathol) 2009. © 2009 American Cancer Society.     

p16INK4a immunocytochemistry versus human papillomavirus testing for triage of women with minor cytologic abnormalities

The best method for identifying women who have minor cervical lesions that require diagnostic workup remains unclear. The authors of this report performed a meta‐analysis to assess the accuracy of cyclin‐dependent kinase inhibitor 2A (p16^INK4a) immunocytochemistry compared with high‐risk human papillomavirus DNA testing with Hybrid Capture 2 (HC2) to detect grade 2 or greater cervical intraepithelial neoplasia (CIN2+) and CIN3+ among women who had cervical cytology indicating atypical squamous cells of undetermined significance (ASC‐US) or low‐grade cervical lesions (LSIL). A literature search was performed in 3 electronic databases to identify studies that were eligible for this meta‐analysis. Seventeen studies were included in the meta‐analysis. The pooled sensitivity of p16^INK4a to detect CIN2+ was 83.2% (95% confidence interval [CI], 76.8%‐88.2%) and 83.8% (95% CI, 73.5%‐90.6%) in ASC‐US and LSIL cervical cytology, respectively, and the pooled specificities were 71% (95% CI, 65%‐76.4%) and 65.7% (95% CI, 54.2%‐75.6%), respectively. Eight studies provided both HC2 and p16^INK4a triage data. p16^INK4a and HC2 had similar sensitivity, and p16^INK4a has significantly higher specificity in the triage of women with ASC‐US (relative sensitivity, 0.95 [95% CI, 0.89‐1.01]; relative specificity, 1.82 [95% CI, 1.57‐2.12]). In the triage of LSIL, p16^INK4a had significantly lower sensitivity but higher specificity compared with HC2 (relative sensitivity, 0.87 [95% CI, 0.81‐0.94]; relative specificity, 2.74 [95% CI, 1.99‐3.76]). The published literature indicated the improved accuracy of p16^INK4a compared with HC2 testing in the triage of women with ASC‐US. In LSIL triage, p16^INK4a was more specific but less sensitive. Cancer (Cancer Cytopathol) 2012. © 2012 American Cancer Society.     

The clinical impact of using p16INK4a immunochemistry in cervical histopathology and cytology: An update of recent developments

Cervical cancer screening test performance has been hampered by either lack of sensitivity of Pap cytology or lack of specificity of Human Papillomavirus (HPV) testing. This uncertainty can lead to unnecessary referral and treatment, which is disturbing for patients and increases costs for health care providers. The identification of p16^INK4a as a marker for neoplastic transformation of cervical squamous epithelial cells by HPVs allows the identification of HPV‐transformed cells in histopathology or cytopathology specimens. Diagnostic studies have demonstrated that the use of p16^INK4a immunohistochemistry substantially improves the reproducibility and diagnostic accuracy of histopathologic diagnoses. p16^INK4a cytology has substantially higher sensitivity for detection of cervical precancer in comparison to conventional Pap tests. Compared to HPV DNA tests, immunochemical detection of p16^INK4a‐stained cells demonstrates a significantly improved specificity with remarkably good sensitivity. About 15 years after the initial observation that p16^INK4a is overexpressed in HPV‐transformed cells we review the accumulated clinical evidence suggesting that p16^INK4a can serve as a useful biomarker in the routine diagnostic work up of patients with HPV infections and associated lesions of the female anogenital tract.     

Role of mucosal high‐risk human papillomavirus types in head and neck cancers in central India

Mucosal high‐risk (HR) human papillomaviruses (HPV) cause a subset of head and neck cancers (HNC). The HPV‐attributable fraction of HNC varies substantially between countries. Although HNC has a very high incidence in the Indian subcontinent, information on the contribution of HPV infection is limited. Here, we evaluated the HPV‐attributable fraction in HNC (N = 364) collected in a central region of India. HNC from three different anatomical subsites were included, namely, oral cavity (n = 252), oropharynx (n = 53) and hypopharynx/larynx (n = 59). In this retrospective study, HPV‐driven HNC were defined by presence of both viral DNA and RNA. Overexpression of p16^INK4a was also evaluated. HR‐HPV DNA was detected in 13.7% of the cases; however, only 2.7% were positive for both HPV DNA and RNA. The highest percentage of HPV DNA/RNA double positivity was found in oropharynx (9.4%), followed by larynx (1.7%) and oral cavity (1.6%) (p = 0.02). More than half of HPV DNA/RNA‐positive cases were p16^INK4a‐negative, while a considerable number of HPV RNA‐negative cases were p16^INK4a‐positive (17.9%). HPV16 was the major type associated with HNC (60.0%), although cases positive for HPV18, 35 and 56 were also detected. Our data indicate that the proportion and types of mucosal HR‐HPV associated with HNC in this central Indian region differ from those in other (developed) parts of the world. This may be explained by differences in smoking and/or sexual behaviour compared with North America and northern Europe. Moreover, we show that p16^INK4a staining appeared not to be a good surrogate marker of HPV transformation in the Indian HNC cases.     

p16INK4a/Ki‐67 co‐expression specifically identifies transformed cells in the head and neck region

p16^INK4a immunohistochemical overexpression is an overall reliable surrogate marker of human papillomavirus (HPV)‐associated head and neck squamous cell carcinomas (HNSCC). However, cases of ambiguous p16^INK4a overexpression are regularly detected in the head and neck: p16^INK4a expression can be observed in non‐malignant tissue, such as tonsillar crypt epithelium and a proportion of branchial cleft cysts. Additionally, diverse patterns of p16^INK4 expression can complicate interpretation of “p16^INK4a‐positivity”. These aspects impede the unrestricted application of p16^INK4a as a diagnostic marker in the head and neck. We hypothesized that combined detection of p16^INK4a and the proliferation marker Ki‐67 could support clarification of ambiguous p16^INK4a expression in the head and neck by specifically indicating p16^INK4a‐expressing cells with proliferative activity. p16^INK4a/Ki‐67 co‐expression in a combined staining procedure was correlated to distinct p16^INK4a expression patterns and HPV status (HPV DNA followed by E6*I oncogene mRNA detection) in 147 HNSCC and 50 non‐malignant head and neck samples. p16^INK4a/Ki‐67 co‐expression only occurred in transformed cells of the head and neck. Co‐expression was never detected in non‐transformed cells. Combined p16^INK4a/Ki‐67 expression was stringently associated with a diffuse p16^INK4a expression pattern. All HPV oncogene‐expressing HNSCC showed p16^INK4a/Ki‐67 co‐expression. We demonstrate that p16^INK4a/Ki‐67 co‐expression occurs exclusively in transformed cells of the head and neck. Our findings indicate a substantial impact of combined p16^INK4a/Ki‐67 expression in the assessment of ambiguous p16^INK4a expression in the head and neck by specifically identifying p16^INK4a‐expressing cells with proliferative activity. This property will be of considerable significance for head and neck histo‐ and cytopathology.     

p16INK4A immunohistochemical staining and predictive value for progression of cervical intraepithelial neoplasia grade 1: A prospective study in China

p16^INK4A is strongly expressed in tissues diagnosed as cervical intraepithelial neoplasia (CIN) and cancer in women infected with human papillomavirus (HPV), but few prospective studies have evaluated p16^INK4A as a marker for the risk of low‐grade CIN (CIN1) progression. We investigated the prevalence of p16^INK4A immunostaining by CIN grade and whether overexpression of p16^INK4A in CIN1 predicts future risk for high‐grade CIN in Chinese women. 6,557 Chinese women aged 30–49 years were screened from 2003 to 2005 using cytology and carcinogenic HPV test. Colposcopy was performed on women with any abnormal result. p16^INK4A Immunostaining was performed on biopsies from all women with CIN1, as well as randomly selected women with normal or CIN grade 2 and worse (CIN2+) biopsies. Women with CIN1 were followed up without treatment. Colposcopy was performed on all untreated women at a 2‐year interval. The prevalence of p16^INK4A staining was 2.7%, 42.7%, 75.5%, 79.6% and 100% among women with normal, CIN1, 2, 3 and cancer biopsies, respectively (p < 0.001). HPV positivity was strongly associated with p16^INK4A staining [odds ratios (OR) = 12.8; 95% confidence intervals (CI): 5.2–31.6]. p16^INK4A staining of CIN1 biopsies at baseline was associated with an increased risk of finding high‐grade CIN over 2 years of follow‐up (OR = 1.43; 95% CI: 0.52–3.91). The two‐year cumulative incidence of CIN2+ for p16^INK4A positive women was higher at 10.71% than for p16^INK4A negative women at 1.30% (crude RR = 8.25, 95% CI: 1.02–66.62). p16^INK4A overexpression is strongly associated with grade of CIN and risk of progression to high‐grade CIN in women with low‐grade lesions.     

The mechanisms by which polyamines accelerate tumor spread

Background

The pathogenic role of beta-HPVs in non melanoma skin cancer (NMSC), is not still completely understood, and literature data indicate that they might be at least cofactors in the development of certain cutaneous squamous cell carcinomas. However, only few reports contain data on basal cell carcinoma (BCC). The HPVs interact with many cellular proteins altering their function or the expression levels, like the p16^INK4a and Akt. Our study aimed to determine the presence of different beta -HPV types and the expression of p16^INK4a and Akt in BCC, the commonest NMSC, in the normal appearing perilesional skin and in forehead swab of 37 immunocompetent patients.

Methods

The expression of p16^INK4a and Akt, by immunohistochemistry, and the HPV DNA, by nested PCR, were investigated in each sample.

Results

No correspondence of HPV types between BCC and swab samples was found, whereas a correspondence between perilesional skin and BCC was ascertained in the 16,7% of the patients. In BCC, 16 different types of beta HPV were found and the most frequent types were HPV107 (15,4%), HPV100 (11,5%) and HPV15 (11,5%) all belonging to the beta HPV species 2. Immunohistochemistry detected significant p16^INK4a expression in almost all tumor samples (94,3%) with the highest percentages (> 30%) of positive cells detected in 8 cases. A statistically significant (p = 0,012) increase of beta HPV presence was detected in p16^INK4a strongly positive samples, in particular of species 2. pAkt expression was detected in all tumor samples with only 2 cases showing rare positive cells, whereas Akt2 expression was found in 14 out of 35 BCC (40%); in particular in HPV positive samples over-expressing p16^INK4a.

Conclusions

Our data show that p16^INK4a and pAkt are over-expressed in BCC and that the high expression of p16^INK4a and of Akt2 isoform is often associated with the presence of beta-HPV species 2 (i.e. HPV 15). The association of these viruses with the up-regulation of p16^INK4a and Akt/PI3K pathway suggests that in a subtype of BCC these viruses may exert a role in the carcinogenesis or in other, still undefined, biological property of these tumors. If this particular type of BCC reflects a different biology it will remain undisclosed until further studies on a larger number of samples will be performed.