International surveys find HPV-negativity in up to 30% of cervical adenocarcinomas. We investigated the pathological diagnosis by expert consensus with immunohistochemistry and the presence of somatic mutations in recognised tumour genes in HPV-positive and negative cervical adenocarcinomas (CADC). A sample was selected of 45 paraffin-embedded cervical blocks diagnosed locally as usual cervical adenocarcinoma from a global study. These represented different diagnoses made at previous diagnostic review and HPV status. All were suitable for analysis for somatic tumour associated gene mutations. Three pathologists examined H/E slides and immunohistochemistry for p16, progesterone receptor and p53 and classified the cases. L1 genes from high-risk HPVs and low-risk HPVs were analysed by SPF10 PCR-DEIA-LiPA25 version 1 in whole tissue sections and microdissected tumour and retested by PCR for E6/E7 genes of hrHPVs if negative. Cases were analysed for microsatellite instability and next-generation sequencing mutation analysis. From the 45 cases, 20 cases of usual CADC were confirmed of which 17 (85%) were HPV-positive in tumour cells. The other 25 cases were reclassified as endometrial, serous, clear-cell and gastric-type adenocarcinomas and all were HPV-negative in tumour cells. Careful retesting for HPV DNA and IHC leads to more accurate identification of HPV-positive usual cervical adenocarcinomas. Endometrioid endometrial adenocarcinomas, other uterine adenocarcinoma with multiple somatic mutations were important in misclassification of HPV-negative cases locally managed as cervical adenocarcinoma, as was gastric-type adenocarcinoma with germline STK11 mutation in East Asia. Few consensuses confirmed HPV-negative usual cervical adenocarcinomas showed somatic tumorigenic mutations also seen in some HPV-positive usual CADC.

Objectives Because current guidelines recognise high-grade anal squamous intraepithelial lesions (HSILs) and low-grade SILs (LSILs), and recommend treatment of all HSILs although not all progress to cancer, this study aims to distinguish transforming and productive HSILs by grading immunohistochemical (IHC) biomarkers p16(INK)(4a) (p16) and E4 in low-risk human papillomavirus (lrHPV) and high-risk (hr)HPV-associated SILs as a potential basis for more selective treatment. Methods Immunostaining for p16 and HPV E4 was performed and graded in 183 biopsies from 108 HIV-positive men who have sex with men. The causative HPV genotype of the worst lesion was identified using the HPV SPF10-PCR-DEIA-LiPA25 version 1 system, with laser capture microdissection for multiple infections. The worst lesions were scored for p16 (0-4) to identify activity of the hrHPV E7 gene, and panHPV E4 (0-2) to mark HPV production and life cycle completion. Results There were 37 normal biopsies, 60 LSILs and 86 HSILs, with 85% of LSILs caused by lrHPV and 93% of HSILs by hrHPV. No normal biopsy showed E4, but 43% of LSILs and 37% of HSILs were E4 positive. No differences in E4 positivity rates were found between lrHPV and hrHPV lesions. Most of the lesions caused by lrHPV (90%) showed very extensive patchy p16 staining; p16 grade in HSILs was variable, with frequency of productive HPV infection dropping with increasing p16 grade. Conclusions Combined p16/E4 IHC identifies productive and nonproductive HSILs associated with hrHPV within the group of HSILs defined by the Lower Anogenital Squamous Terminology recommendations. This opens the possibility of investigating selective treatment of advanced transforming HSILs caused by hrHPV, and a 'wait and see' policy for productive HSILs. What's already known about this topic? For preventing anal cancer in high-risk populations, all patients with high-grade squamous intraepithelial lesions (HSILs) are treated, even though this group of lesions is heterogeneous, the histology is variable and regression is frequent. What does this study add? By adding human papillomavirus (HPV) E4 immunohistochemistry to p16 (INK4a) (p16), and grading expression of both markers, different biomarker expression patterns that reflect the heterogeneity of HSILs can be identified. Moreover, p16/E4 staining can separate high-risk HPV-associated HSILs into productive and more advanced transforming lesions, providing a potential basis for selective treatment.

With increasing use of p16 immunohistochemistry (IHC) in diagnosis of premalignant lesions of cervix, we occasionally encounter p16 positivity in squamous metaplasia that lacks morphologic characteristics of "atypical squamous metaplasia" or of squamous intraepithelial lesion (SIL). Our study aims to investigate if transcriptionally active human papilloma virus (HPV) can be identified in such foci and if they have any relationship with squamo-columnar junction (SCJ) cells. Twenty-two cases of cervical specimens with at least a focus of p16 positive bland squamous metaplasia, were selected. HPV E6/E7 mRNA in situ hybridization followed by IHC for CK7 (SCJ biomarker), Ki67, and HPV16 E2, were performed. Follow-up information was obtained. Four cases were excluded due to insufficient tissue. Of the final 18 cases, HPV E6/E7 mRNA in situ hybridization was positive in all. Nine cases showed positivity in >50% cells and the epithelial thickness involved was ≥lower two-thirds in 13 cases. Of the further evaluable 15 cases, CK7 was positive in 14, Ki67 was positive in 10, and HPV16 E2 was negative in all. Concomitant high-grade squamous intraepithelial lesion was identified in 10 cases. On follow-up (duration: 1 to 19 mo), 6 patients showed histologic high-grade squamous intraepithelial lesion. Our study demonstrates that p16 positivity in squamous metaplasia of cervix is associated with the presence of transcriptionally active high-risk HPV even when there are no clear morphologic features of dysplasia. Our results suggest that these lesions are early SILs or SILs that are not yet morphologically evident, most of which arise from SCJ and should be closely followed.

Gastric-type endocervical adenocarcinoma (GAS) is a recently described diagnostic entity originally characterized as a tumor with (1) voluminous cytoplasm that is (2) clear or pale eosinophilic, and (3) cells showing distinct cell borders. Since the initial tumor description there has been accumulating experience that the neoplasm, in addition to classic features, may show a wide spectrum of morphologic appearances. This paper describes and illustrates cases of GAS with focal or diffuse findings that include: densely eosinophilic cytoplasm, foamy cytoplasm, goblet cells, glands with elongated, stratified nuclei, glands with small cuboidal cells, glands with flattened cells, papillary growth, single cell infiltration and infiltration with microcystic elongated and fragmented pattern. All these patterns may bring up a differential diagnosis with other cervical malignancies such as usual, intestinal, endometrioid, clear cell, serous, and mesonephric adenocarcinoma. The paper describes the patterns of immunostaining of respective lesions that may aid in the diagnostic process and summarizes the main points of the differential diagnosis. GAS is associated with somatic and germline STK11 mutations and TP53 mutations but is invariably negative for human papilloma virus when tumor only is tested. It shows variation in incidence between countries. Awareness of the spectrum of morphologic appearances in GAS is important for accurate and confident diagnosis. Correct identification of GAS is important due to its propensity for ovarian and other distant metastases, markedly worse prognosis as compared with usual endocervical adenocarcinoma, and its relative resistance to chemotherapy.

The aim of this study is to determine whether immunohistochemistry for Stathmin-1 enhances diagnostic accuracy of anal dysplasia. The study included 40 biopsies with diagnosis of benign anal transitional zone (n=10), low-grade anal intraepithelial neoplasia (AIN) (AIN1, n=10), and high-grade AIN (AIN2, n=10, AIN3, n=10). The cases were selected to represent classic features. Immunohistochemistry for Stathmin-1, p16, and Ki-67 was performed and assessed for distribution within epithelial thickness. Stathmin-1 was expressed only in the basal layer of benign anal epithelium. Similar pattern of distribution was seen in all low-grade AIN cases (100%). In total, 40% of AIN2 showed Stathmin-1 staining pattern similar to AIN1. The other 60% of cases showed staining extending into the middle third of the epithelial thickness. Of AIN3 cases, 20% showed staining confined to the lower third epithelium, 20% showed staining extending to the middle third, and 60% showed staining extending into the upper third epithelium. The pattern of stain distribution suggested that staining extending above the lower one-third of the epithelial thickness discriminates between low-grade and high-grade AIN. With this cutoff, the sensitivity for the diagnosis of high-grade AIN was 70%, specificity was 100%, positive predictive value equaled 100%, and negative predictive value equaled 77%. P16INK4a showed 100% sensitivity for AIN2 and AIN3, whereas Ki-67 had 100% sensitivity for any AIN grade. In conclusion, Stathmin-1 has excellent specificity for the diagnosis of high-grade AIN; however, Stathmin-1 alone may not be sufficiently sensitive. Use in conjunction with other sensitive markers, such as p16 or Ki-67 may be considered.

Background: Immunohistochemical (IHC) biomarkers enable standardised, reproducible grading of anal intraepithelial neoplasia (AIN) based on progression of HPV infection from transient productive infection to complete neoplastic transformation. We investigated the expression of IHC biomarker HPV E4, a marker of productive HPV infection, in different grades of AIN caused by low-risk (lr) and high-risk (hr) HPV infection. Methods: A reference grading of AIN was established using expert, consensus, subjective HE diagnoses supported by p16 expression for 183 anal biopsies: normal squamous epithelium 37, AIN1 67, AIN2 43, AIN3 36. Causative HPV genotype of the worst lesion was identified using laser capture microdissection and SPF10-PCR. Results: Most AIN1 lesions were caused by lrHPV (72%) whereas most AIN2 (84%) and AIN3 (92%) was caused by hrHPV. None of the normal biopsies showed E4 positivity and 49% (33/67) of AIN1, 56% (24/43) of AIN2 and 3% (1/36) of AIN3 showed E4 positivity. While the large majority of E4 positive AIN1 (26/33) and AIN2 (16/24) lesions showed extensive positivity, the E4 positive AIN3 lesion showed only focal, superficial E4 positivity. HPV E4 positivity was seen in lesions caused by lr and hr HPV. Conclusions: Our results show that when using HPV E4 in addition to p16, productive infections among both low-grade and high-grade AIN can be identified. Studies that further explore progression and regression in transforming (E4 negative) and productive (E4 positive) high-grade AIN, are necessary.

Background: Prevention of cervical cancer is based upon the accurate diagnosis and grading of cervical lesions identified during screening. The pathological classification of cervical intraepithelial neoplasia (CIN) is problematic, as it relies on subjective criteria and is known to have high interobserver variability and low reproducibility. These limitations can result in either over or under treatment of patients. Biomarkers to improve CIN diagnosis have not overcome all these challenges. Main body: Here we review the use of a promising optical imaging method using eosin-based fluorescence spectroscopy. This technique is able to perform fluorescent analysis of cervical biopsies directly from hematoxylin and eosin (H&E) stained tissues. Eosin is a brominated derivative of fluorescein. Fluorescence characteristics of protein-eosin complexes can demonstrate tissue changes associated with dysplasia and cancer. In this article we review the progress made towards developing eosin-based fluorescence spectroscopy. We describe the various morphologies seen among the CIN grades with this optical method and highlight the progress made to quantitate the spectral image characteristics. Conclusion: Eosin-based fluorescence spectroscopy can be used to directly examine H&E stained tissue slides. Relevant areas can be imaged and spectral analysis done to obtain objective data to identify and grade cervical lesions.

Objective A hospital-based multicenter, retrospective study was conducted to compare the distribution of human papillomavirus (HPV) in squamous cell carcinoma (SCC) and cervical adenocarcinoma (CADC) in China. Methods Paraffin-embedded tissue blocks diagnosed as SCC and CADC across China were collected, as well as the total number of diagnosed invasive cervical cancer of the 9 selected centers. DNA enzyme immunoassay, reverse hybridization, and multiplex type-specific polymerase chain reaction were used for HPV genotyping. Results The ratios of CADC to SCC were increasing from 2005 to 2010, in parallel with HPV prevalence in CADC. In 630 patients with SCC (mean ± SD age, 45.40 ± 10.30) and 718 patients with CADC (mean ± SD age, 46.09 ± 10.59) recruited, HPV prevalence rates were 97.6% and 74.5%, respectively. Human papillomavirus viral load for SCC is significantly higher than that for CADC. Most common HPV types distributed in SCC and CADC were HPV-16 (78.5%, 75.1%–81.6%; 47.1%, 42.9%–51.3%), HPV-18 (8.0%, 6.1%–10.4%; 41.1%, 37.0%–45.3%), HPV-52 (2.3%, 1.4%–3.8%; 5.6%, 4.0%–7.9%), and HPV-45 (1.1%, 0.6%–2.3%; 3.9%, 2.6%–5.9%). Different diagnostic mean ± SD age for HPV-16/HPV-18 versus other high-risk HPV types were observed: SCC (44.5 ± 9.94 vs 51.0 ± 10.83, p < .05) and CADC (44.1 ± 9.44 vs 47.4 ± 10.41, p = .006). For HPV-negative cases, mean ± SD age was 46.1 ± 10.73 in SCC and 50.3 ± 11.85 in CADC, which were older than the positive (45.4 ± 10.31, 44.5 ± 9.64). HPV-16 and HPV-18 were the most frequent HPV types in both histological types, and HPV-18 was more frequent in CADC than in SCC. Conclusions Human papillomavirus infection was identified more often in SCC than in CADC. Women with HPV-associated cancers, especially HPV-16/HPV-18, were of a younger age at diagnosis when compared with non–HPV-associated cancers.

Progression of anal intraepithelial neoplasia (AIN) involves transition from productive to transforming human papillomavirus (HPV) infection. Grading aims to distinguish productive low-grade AIN from high-grade anal intraepithelial neoplasia (HGAIN) with risk of cancer. We describe immunohistochemical patterns in AIN adding a novel marker for initiation of the productive phase of the HPV life cycle (panHPVE4) to those for cell cycle activity (Ki-67) and transforming activity of HPVE7 gene (p16). We studied 67 anal biopsies for suspected anal neoplasia (17 normal, 15 AIN1, 20 AIN2, 15 AIN3) from 54 men who have sex with men at New York Presbyterian Hospital, USA. Two pathologists generated consensus AIN and immunogrades. Whole tissue and laser capture microdissection samples from multiple HPV-infected biopsies were tested for HPV with SPF10-PCR-DEIA-LiPA25, version 1. (Para)basal Ki-67 expression distinguished normal from AIN (≥lower-third Ki-67) with sensitivity 0.92 and specificity 1.0. Ki-67 did not distinguish grades of AIN. Null/patchy p16 versus diffuse ≥lower-third patterns discriminated HGAIN (sensitivity, 1.0; specificity, 0.84). There was marked heterogeneity in E4 expression within HGAIN. Most AIN2 (14/20) was E4+ versus 0/15 AIN3 (sensitivity, 0.70; specificity 1.0). HPV was detected in 63 (94%) biopsies, with 49 (77.8%) high-risk HPV+. HPV16 was the most frequent (13%). Multiple HPV genotypes were found in 15 (24%) biopsies and laser capture microdissection -polymerase chain reaction confirmed specific HPV types in E4 +/− AIN. Although Ki-67 discriminated AIN and p16 HGAIN, E4+/p16+ staining shows that most AIN2 is different from transformed AIN3 in showing both entry into productive HPV infection and transforming activity.

Cervical adenocarcinomas are a group of malignancies with several distinct histologic tumor types, which include endocervical usual type, endometrioid, intestinal, villoglandular, gastric, signet ring, serous, clear cell, and mesonephric. Diagnosis of cervical adenocarcinoma, in particular early diagnosis, and classification of the tumor type may pose a significant challenge. The goal of this article is to review the current classification, diagnostic criteria, adjunct markers, and differential diagnosis of various subtypes of cervical adenocarcinomas. The article presents up-to-date summary of such problematic issues as differentiating glandular tumors from benign mimics, differentiating early invasive lesions from adenocarcinoma in situ, determining the tumor type, and, finally, differentiating primary cervical adenocarcinoma from uterine endometrioid adenocarcinoma. Discussion of human papillomavirus detection in different tumor types is provided.

Historically, endometrial carcinomas have been classified primarily according to their histology. However, the use of immunohistochemistry has become commonplace in their evaluation, particularly in diagnostically challenging cases. Our objective was to evaluate mixed endometrial carcinomas using a well-established panel of biomarkers to assess the consistency and utility of these stains in clinical diagnosis. Eighteen cases comprised of various combinations of classical serous (SC), endometrioid (EC), and clear cell (CC) morphologies were identified and subjected to a panel of immunohistochemical markers including p53, p16, Ki67, estrogen receptor, progesterone receptor, and Napsin A. Intensity and extent of staining were evaluated on 4-tiered and 5-tiered scales, respectively. The typical immunostaining pattern expected for the individual tumor components was seen in only 3 cases, while in 15 cases an unexpected pattern was observed with at least one immunomarker. By tumor type, the most common unexpected finding in EC/SC carcinoma cases was diffuse positivity for p16 and/or estrogen receptor/progesterone receptor in both components, while in SC/CC, diffuse positivity for p53 in both components was most frequently seen, and in SC/CC/EC, Napsin A negativity was most commonly observed. Despite displaying diagnostic morphology, components of many mixed endometrial carcinomas may not exhibit expected immunohistochemical features. This may be due to the fact that these carcinomas arise from a single clone with subsequent divergence, resulting in a tumor with both mixed histologic and genetic features. It is important to note that these tumors may not demonstrate the immunohistochemical prototype of their constituents and should be approached accordingly from a diagnostic perspective.

Hereditary leiomyomatosis renal cell cancer syndrome is an autosomal dominant disorder characterized by uterine and cutaneous leiomyomas and increased predisposition to renal cell carcinoma, papillary type II. The syndrome is caused by heterozygous mutations to the fumarate hydratase (FH) gene located on chromosome 1. Affected females generally present with early onset, atypical uterine leiomyomas and cutaneous findings, however, delays in diagnosis are very common in patients with isolated uterine findings. We present a case series of 2 sisters in their 20s who presented with isolated uterine leiomyomas and were found to carry a novel mutation for the fumarate hydratase gene. One patient was referred for treatment of infertility and recurrent miscarriages and the other was referred for acute symptomatic anemia due to myomas. Prompt diagnosis of hereditary leiomyomatosis renal cell cancer was made due to a high index of clinical suspicion based on early onset disease and familial clustering as well as characteristic pathologic findings on uterine leiomyoma surgical specimen. Timely diagnosis not only allowed for genetic counseling and renal cancer surveillance, but also for fertility counseling given the increased morbidity associated with uterine leiomyoma due to hereditary leiomyomatosis and renal cell cancer syndrome.

Context.-Cervical adenocarcinomas span a diverse group of tumors with several distinct histologic tumor types, which include endocervical, endometrioid, intestinal, villoglandular, gastric, signet ring, serous, clear cell, and mesonephric. Diagnosis of cervical adenocarcinoma, especially early diagnosis, poses a significant challenge. Objective.-To review the pathogenesis, diagnostic criteria, immunohistochemical markers, and differential diagnosis of various subtypes of human papillomavirus (HPV)-positive and HPV-negative cervical adenocarcinomas. The paper presents a concise summary of the issues that may be particularly difficult in histopathologic diagnosis, such as differentiating neoplastic lesions from benign mimics, determining the tumor type, differentiating early invasive lesions from adenocarcinoma in situ, measuring the depth of invasion, and, finally, differentiating primary cervical adenocarcinoma from uterine endometrioid adenocarcinoma and tumors metastatic from other primary sites. Data Sources.-The study employed a PubMed search of recently published reports. Conclusions.-Early detection of HPV-positive tumor types may be aided with the expansion of HPV testing; however, early diagnosis of HPV-negative cervical adenocarcinomas will continue to pose a challenge and may require the development of additional molecular testing techniques.

The goal of the study was to examine expression of prostate-specific membrane antigen (PSMA) in neovasculature of gynecologic cancers, as PSMA-targeted therapy has showed a promise in treatment of advanced carcinomas. The study included cervical carcinoma (n=28), vulvar carcinoma (n=20), endometrial carcinoma (n=23), primary ovarian carcinoma (n=21), metastatic ovarian carcinoma (n=25), and normal cervix (n=12) as negative control. All cases were immunostained using anti-CD31 antibody to delineate capillary endothelial cells. In parallel, all cases were immunostained using anti-PSMA antibody. The PSMA staining was assessed in tumor capillaries and in normal tissues and scored as a percentage of CD31 staining. PSMA expression was found in the tumor neovasculature, and no significant expression was identified in vasculature of normal tissues. The extent of PSMA staining in tumor capillaries varied from high expression in ovarian and endometrial cancers, to medium expression in cervical squamous cell carcinomas, and low expression in cervical adenocarcinomas and vulvar cancers. All (100%) cases of primary ovarian carcinoma, ovarian carcinoma metastases, and primary endometrial carcinoma showed PSMA expression in tumor vasculature, which was diffuse in majority of cases. The expression of PSMA in ovarian cancer metastases was similar among different metastatic foci of the same tumor. Fifteen percent of cervical squamous cell carcinoma, 50% of cervical adenocarcinoma, and 75% of vulvar carcinomas showed no capillary expression of PSMA. In conclusion, PSMA is highly and specifically expressed in the neovasculature of ovarian, endometrial, and cervical squamous carcinoma, rendering it a potential therapeutic vascular target.

Diagnostic CytopathologyVolume 44, Issue 8 p. 710-713 Letter to the Editor Cytomorphology of Gastric-Type Cervical Adenocarcinoma on a ThinPrep Pap Test: Report of a p16-Positive Tumor Case Clifton G. Fulmer M.D., PH.D, Corresponding Author Clifton G. Fulmer M.D., PH.D Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkCorrespondence to: Clifton G. Fulmer, MD, PhD, Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New York, USA. E-mail: cgf9001@nyp.orgSearch for more papers by this authorRana S. Hoda M.D., F.I.A.C., Rana S. Hoda M.D., F.I.A.C. Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkSearch for more papers by this authorEdyta C. Pirog M.D., PH.D., Edyta C. Pirog M.D., PH.D. Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkSearch for more papers by this authorKay J. Park M.D., Kay J. Park M.D. Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New YorkSearch for more papers by this authorKevin Holcomb M.D., F.A.C.O.G., Kevin Holcomb M.D., F.A.C.O.G. Gynecologic Oncology Division, Department of Obstetrics and Gynecology, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkSearch for more papers by this author Clifton G. Fulmer M.D., PH.D, Corresponding Author Clifton G. Fulmer M.D., PH.D Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkCorrespondence to: Clifton G. Fulmer, MD, PhD, Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New York, USA. E-mail: cgf9001@nyp.orgSearch for more papers by this authorRana S. Hoda M.D., F.I.A.C., Rana S. Hoda M.D., F.I.A.C. Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkSearch for more papers by this authorEdyta C. Pirog M.D., PH.D., Edyta C. Pirog M.D., PH.D. Department of Pathology & Laboratory Medicine, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkSearch for more papers by this authorKay J. Park M.D., Kay J. Park M.D. Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New YorkSearch for more papers by this authorKevin Holcomb M.D., F.A.C.O.G., Kevin Holcomb M.D., F.A.C.O.G. Gynecologic Oncology Division, Department of Obstetrics and Gynecology, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, New YorkSearch for more papers by this author First published: 11 May 2016 https://doi.org/10.1002/dc.23498Citations: 5 Disclosure Statement: The Authors have no disclosure. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume44, Issue8August 2016Pages 710-713 RelatedInformation

BACKGROUND:We conducted a large international study to estimate fractions of head and neck cancers (HNCs) attributable to human papillomavirus (HPV-AFs) using six HPV-related biomarkers of viral detection, transcription, and cellular transformation.METHODS:Formalin-fixed, paraffin-embedded cancer tissues of the oral cavity (OC), pharynx, and larynx were collected from pathology archives in 29 countries. All samples were subject to histopathological evaluation, DNA quality control, and HPV-DNA detection. Samples containing HPV-DNA were further subject to HPV E6*I mRNA detection and to p16(INK4a), pRb, p53, and Cyclin D1 immunohistochemistry. Final estimates of HPV-AFs were based on HPV-DNA, HPV E6*I mRNA, and/or p16(INK4a) results.RESULTS:A total of 3680 samples yielded valid results: 1374 pharyngeal, 1264 OC, and 1042 laryngeal cancers. HPV-AF estimates based on positivity for HPV-DNA, and for either HPV E6*I mRNA or p16(INK4a), were 22.4%, 4.4%, and 3.5% for cancers of the oropharynx, OC, and larynx, respectively, and 18.5%, 3.0%, and 1.5% when requiring simultaneous positivity for all three markers. HPV16 was largely the most common type. Estimates of HPV-AF in the oropharynx were highest in South America, Central and Eastern Europe, and Northern Europe, and lowest in Southern Europe. Women showed higher HPV-AFs than men for cancers of the oropharynx in Europe and for the larynx in Central-South America.CONCLUSIONS:HPV contribution to HNCs is substantial but highly heterogeneous by cancer site, region, and sex. This study, the largest exploring HPV attribution in HNCs, confirms the important role of HPVs in oropharyngeal cancer and drastically downplays the previously reported involvement of HPVs in the other HNCs.