Evaluation of high-risk human papillomavirus in sinonasal papillomas and squamous cell carcinomas

The sinonasal tract is considered a second hotspot for human papillomavirus (HPV)-related tumors in the head and neck, with HPV being identified in up to 62% of squamous cell carcinomas (SCCs) and 38% of papillomas. There is limited data from geographical regions with low prevalence of high-risk (HR)-HPV on the association of HR-HPV in sinonasal neoplasms and on utility of p16 as a surrogate marker. p16 immunohistochemistry, HR-HPV mRNA ISH and quantitative real-time PCR (qPCR) were performed on a retrospective cohort of sinonasal papillomas and SCCs. KRAS mutation analysis was done in oncocytic papillomas. p16 positivity was present in 22/142 cases (15.5%) including eight inverted papillomas, one oncocytic papilloma (OP), and 13 SCC. Among these, mRNA ISH showed HR-HPV in the OP and two SCC, while another SCC was found to harbour HPV18 by qPCR. Two HPV-associated SCCs had foci of OP. mRNA ISH was negative in all p16 negative cases. p16 immunohistochemistry showed 68% concordance with mRNA ISH, and had sensitivity and negative predictive value of 100%; specificity was 67%, and positive predictive value was 14.3%. Association with HR-HPV in sinonasal papillomas and SCC is rare, and may be seen in cases demonstrating oncocytic morphology. p16 immunohistochemistry has low specificity and positive predictive value in low-prevalence populations; thus, reflex direct HR-HPV testing should be performed in p16 immunopositive cases. This two-step approach is viable in resource-limited settings, as the proportion of p16 positive cases is small.

Penile intraepithelial neoplasia: Distribution of subtypes, HPV genotypes and p16(INK4a) in 84 international cases

There are few pathologic or molecular studies of penile precancerous lesions, and the majority refers to lesions associated with invasive carcinomas. Penile Intraepithelial Neoplasia (PeIN) is classified in two morphologically and distinctive molecular groups, non-HPV and HPV-related with special subtypes. The primary purpose of this international series was to classify PeIN morphologically, detect HPV genotypes and determine their distribution according to PeIN subtypes. A secondary aim was to evaluate the p16^INK4a immunostaining as a possible HPV surrogate for high-risk HPV infection in penile precancerous lesions. Samples consisted of 84 PeIN cases, part of a retrospective cross-sectional analysis of 1095 penile carcinomas designed to estimate the HPV DNA prevalence in penile cancers using PCR and p16^INK4a immunostaining. Penile Intraepithelial Neoplasia (PeIN) was classified in HPV-related (basaloid, warty-basaloid, warty, hybrid, and mixed subtypes) and non-HPV-related (differentiated), the former being the most frequent. PeIN subtypes were differentiated (non-HPV-related) and basaloid, warty-basaloid, warty, hybrid and mixed (HPV-related). Basaloid PeIN was the most commonly diagnosed subtype, and HPV16 was the most frequent HPV genotype detected. Warty-basaloid and warty PeIN showed a more heterogeneous genotypic composition. Most HPV genotypes were high-risk but low-risk HPV genotypes were also present in a few cases (4%). A single HPV genotype was detected in 82% of HPV positive cases. In contrast, multiple genotypes were detected in the remaining 18% of cases. The findings in this study support the paradigm that penile in situ neoplasia, like its invasive counterparts, is HPV dependent or independent and has distinctive morphological subtypes readily identified in routine practice. Considering that HPV16 is clearly the predominant type, and that the three available vaccines have HPV16, all of them will be suitable for vaccination programs; the price of the vaccines will be probably the main determinant to choose the vaccine.

Prognostic Value of HPV Infection Assessed by p16 Immunohistochemistry and the Influence of Tobacco Usage in Oropharyngeal Cancers: Real World Scenario

To find if an association could be established between Human Papilloma Virus (HPV) infection and oropharyngeal cancers (OPCs) in a group of patients known to be regular users of tobacco, and to determine the impact of HPV status on clinical outcomes.Case records of 212 patients with AJCC-7 (The American Joint Committee on Cancer 7th edition) stages II-IVB non metastatic squamous cell carcinoma of the oropharynx treated using radical radiotherapy with or without chemotherapy during the years 2015-2018 were retrieved. Formalin-fixed, paraffin-embedded blocks from oropharyngeal biopsies were available for 177 patients and were evaluated for p16 expression by immunohistochemical (IHC) staining. More than 50% nuclear staining with or without cytoplasmic staining was considered HPV+ . The association between tobacco use and HPV, as well as the influence of HPV status on survival outcomes were assessed. p16 expression was found to be positive in 23(13%) patients. Significant association was found between chewable tobacco usage and HPV positivity (p = 0.051). The median follow up was 20.5 months (range: 3-80). 5-year Overall Survival was 43.4% and 29.8% (p = 0.044) in HPV+ and HPV- patients, respectively. Local control was significantly better in HPV+ patients (38.6% vs. 25.3%, p = 0.049). There was also a trend towards improved Disease-free Survival in HPV+ patients (31 months vs. 15 months, p = 0.078). Though less in prevalence among the Indian population, improved outcomes in HPV+ OPC patients and widely available IHC HPV assays signifies the routine implementation of p16 testing in day-to-day clinical practice.

Human Papillomavirus-Associated Oral Cavity Squamous Cell Carcinoma: An Entity with Distinct Morphologic and Clinical Features

BACKGROUND

HPV-associated oral cavity squamous cell carcinoma (SCC) is not well-characterized in the literature, and also has a clinical significance that is poorly understood.

METHODS

We gathered a cohort of oral cavity (OC) SCC with nonkeratinizing morphology, either in the invasive or in situ carcinoma (or both), tested for p16 by immunohistochemistry and high risk HPV E6/E7 mRNA by RTPCR (reference standard for transcriptionally-active high risk HPV) and gathered detailed morphologic and clinicopathologic data.

RESULTS

Thirteen patients from two institutions were proven to be HPV-associated by combined p16 and high risk HPV mRNA positivity. All 13 patients (100%) were males, all were heavy smokers (average 57 pack/year), and most were active drinkers (9/11 or 81.8%). All 13 (100%) involved the tongue and/or floor of mouth. All had nonkeratinizing features, but maturing squamous differentiation varied widely (0-90%; mean 37.3%). Nonkeratinizing areas had high N:C ratios and larger nests, frequently with pushing borders, and minimal (or no) stromal desmoplasia. The carcinoma in situ, when present, was Bowenoid/nonkeratinizing with cells with high N:C ratios, full thickness loss of maturation, and abundant apoptosis and mitosis. HPV was type 16 in 11 patients (84.6%) and type 33 in two (15.4%). Nine patients had treatment data available. These underwent primary surgical resection with tumors ranging from 1.6 to 5.2 cm. Most had bone invasion (6/9-66.7% were T4a tumors), and most (6/9-66.7%) had extensive SCC in situ with all 6 of these patients having final margins positive for in situ carcinoma.

CONCLUSIONS

HPV-associated OCSCC is an uncommon entity that shows certain distinct clinical and pathologic features. Recognition of these features may help pathologic diagnosis and could potentially help guide clinical management.

The utility of high-risk human papillomavirus in situ hybridization in cytology cell block material from cystic head and neck lesions

BACKGROUND

Human papillomavirus-related oropharyngeal squamous cell carcinoma (HPV-OPSCC) presents frequently as metastasis in a neck lymph node that may be cystic or necrotic. Fine-needle aspiration (FNA) biopsies are often first-line diagnostic procedures. p16 immunohistochemistry (IHC) is a surrogate marker for high-risk HPV (hrHPV) infection but can be challenging to interpret. This study evaluated the use of hrHPV in situ hybridization (ISH) in cytology cell blocks of cystic neck lesions.

METHODS

Twenty-four FNA cases with cell blocks and surgical correlates were evaluated. p16 IHC and hrHPV ISH were assessed on cell blocks (C-p16 and C-hrHPV ISH), and hrHPV ISH on surgical samples (S-hrHPV ISH). All results were classified as negative, positive, or equivocal.

RESULTS

Two cases were excluded because of insufficient tissue on recut. On the basis of C-hrHPV ISH cases, 12 were positive, 5 were negative, and 5 were equivocal. All 12 positive C-hrHPV ISH cases had concordant S-hrHPV ISH with no false positives. Of the 5 negative C-hrHPV ISH cases, 4 had concordant S-hrHPV ISH, and 1 had a discordant S-hrHPV ISH. Of the 5 equivocal C-hrHPV ISH cases, S-hrHPV ISH were both positive and negative. Fourteen cases were equivocal by C-p16; 9 cases were reliably classified by C-hrHPV ISH (5 positive, 4 negative; 64%).

CONCLUSIONS

C-hrHPV ISH can be reliably used, especially when positive. A negative or equivocal interpretation of C-hrHPV ISH may warrant repeat testing. Compared to C-p16, C-hrHPV ISH is more frequently diagnostic and could be helpful for HPV-OSCC diagnosis and management.

2020 WHO Classification of Female Genital Tumors

The 2020 WHO classification is focused on the distinction between HPV-associated and HPV-independent squamous cell carcinoma of the lower female genital organs. Differentiating according to HPV association does not replace the process of grading; however, the WHO classification does not recommend any specific grading system. VIN are also differentiated according to whether they are HPV(p16)-associated. HPV-independent adenocarcinoma (AC) of the cervix uteri has an unfavorable prognosis. Immunohistochemical p16 expression is considered to be a surrogate marker for HPV association. HPV-associated AC of the cervix uteri is determined using the prognostically relevant Silva pattern.

Metastatic HPV-Associated Oropharyngeal Versus Primary Pulmonary Squamous Cell Carcinoma: is p16 Immunostain Useful?

The lungs are a common site of metastasis of head and neck (H&N) squamous cell carcinomas (SCC). This study attempts to define p16 immunoexpression and presence of HPV in primary SCC of the lung and determine their usefulness in discriminating between primary lung SCC and metastasis from HPV-associated oropharyngeal primary. Pathology archives were searched for patients with SCC of the lung without SCC elsewhere. Tissue microarray was constructed and immunohistochemistry performed using anti-p40 and anti-p16 antibodies. All cases were tested for HPV viral proteins E6/E7 by RNA in situ hybridization (ISH) and available positive cases for HPV DNA by polymerase chain reaction (PCR). Eight of 25 (32%) showed cytoplasmic and nuclear expression of p16: 2 (8%) strong and 2 (8%) moderate in > 70% of tumor cells; 1 (4%) strong, 1 (4%) moderate, and 1 (4%) weak in 50-70% of tumor cells; 1 (4%) weak in < 50% of tumor cells. E6/E7 mRNA ISH was negative in all cases. Seven of 8 (87.5%) p16-expressing cases were available for testing by HPV PCR; all were negative for HPV DNA. A retrospective control group of 12 patients with possible SCC metastatic to lung was also identified; high-risk HPV DNA was present in 3, confirming metastasis. p16 expression in lung SCC is not uncommon and may not discriminate between primary pulmonary SCC and metastasis from HPV-associated oropharyngeal primary. Confirmatory HPV testing (high risk HPV DNA or E6/E7 mRNA) is recommended to differentiate metastasis from oropharyngeal primary from two separate primaries.

Tissue Fixation Conditions for p16 Immunohistochemistry and Human Papillomavirus RNA In Situ Hybridization in Oropharyngeal Squamous Cell Carcinoma

Human papillomavirus (HPV) has become a critical prognostic biomarker in oropharyngeal squamous cell carcinoma (OPSCC). While retrospective studies suggest that p16 immunohistochemistry and even HPV RNA in situ hybridization work well on tissues and tumors from a variety of labs and various fixation conditions, no formal study of fixation conditions has been performed to date. We took surgically resected specimens from three p16 and HPV RNA in situ hybridization positive OPSCC patients, divided their fresh tumors into small pieces, and varied the time to formalin fixation as 1, 3, 6, 24, and 48 h. Tumors were either held moistened at room temperature or were refrigerated. After fixation and processing, routine hematoxylin and eosin slides were generated and p16 immunohistochemistry and RNA in situ hybridization performed. All three tumors were nonkeratinizing and had strong and diffuse p16 expression at immediate fixation, which, surprisingly, remained positive for all fixation times and conditions and despite significant degeneration at the later points for two of the patients while for one, the nuclear signal dropped out of most cells at early and mid time points, particularly at room temperature, causing false negatives. HPV RNA in situ hybridization stayed positive in all specimens up to 48 h of cold ischemic time refrigerated and even at room temperature, except for overtly autolyzed tumor regions. These findings help to establish that, at least for standard nonkeratinizing, p16 and HPV RNA strongly positive OPSCC patients, and using the most common tests in clinical practice, relatively lenient time to fixation may be acceptable if it cannot be avoided. However, for some patients, p16 immunohistochemistry may be sensitive to signal loss with autolysis. HPV RNA in situ hybridization, in particular, seems remarkably resistant to pretest cold ischemic times.

Are Histomorphological Features Predictive of p16 Immunopositivity Different for Oral and Oropharyngeal Squamous Cell Carcinoma?

Evidence from current studies show that squamous cell carcinomas at oral and oropharyngeal sites are distinct and unique, with their own separate etiopathogenesis, treatment, and prognosis. The aim of this work is to correlate p16 immunohistochemical expression with histomorphological features suggestive of HPV infection in oral and oropharyngeal squamous cell carcinoma. A total of 50 consecutive biopsy cases of oral squamous cell carcinoma (OSCC) and 50 consecutive biopsy cases of oropharyngeal squamous cell carcinoma (OPSCC) were evaluated for features suggestive of HPV infection like focal basaloid appearance, nests, and lobules of tumor cells with pushing borders, absence of stromal reaction, central necrosis, focal lymphoepithelial morphology, presence of koilocytes, and non-keratinizing or hybrid morphology. Immunostaining was performed using p16 monoclonal antibody (clone mouse 16P04). Only cases showing a moderate (2+) to high intensity (3+) staining in more than 75% cells were taken as p16 immunopositive. The histological features were correlated with p16 immunopositivity. A total of 18/50 (36%) cases of oral squamous cell carcinoma and 27/50 (54%) cases of oropharyngeal squamous cell carcinoma were p16 immunopositive. On statistical analysis, only nests/lobules with pushing borders were found to have a significant correlation with p16 immunopositivity (P value = 0.0012) for OSCC cases. For OPSCC cases, four histological features namely nests and lobules with pushing borders (P value = 0.0001), focal basaloid appearance (P value = 0.0041), lymphoepithelial morphology (P value = 0.0029), and non-keratinizing/hybrid morphology (P value = 0.0141) had a significant correlation with p16 immunopositivity. Histomorphological features are more helpful in predicting p16 immunopositivity in OPSCC than OSCC.

P16 and human papillomavirus in sinonasal squamous cell carcinoma

Human papillomavirus (HPV) in oropharyngeal squamous cell carcinoma (SCC) is a well-known cause and prognostic indicator, and the utility of p16 as a surrogate marker for HPV status has been established. P16 and its relationship with HPV have not been defined in sinonasal malignancy nor has a link with outcomes been established. Patients with sinonasal SCC from 2011 to 2017 were identified from our pathology database. P16 immunohistochemistry and HPV RNA in situ hybridization were performed on tissue specimens. Forty-seven patients were included. Disease-free survival for p16+ patients was significantly higher than p16- patients (P = .043). Fewer HPV+ patients died (P = .052) or experienced recurrence (P = .0437). Odds ratio between p16 and HPV status was 14.19 (95% CI: 1.72, 442.03). Our findings demonstrate improved survival in both the p16+ and HPV+ groups and a positive association between p16 and HPV. There may be similar potential for modifying classification for HPV+ sinonasal SCC.

p16 Expression Correlates with Invasive Ocular Surface Squamous Neoplasms in HIV-Infected Mozambicans

BACKGROUND

p16 immunohistochemistry is widely used to diagnose human papillomavirus (HPV)-related squamous neoplasms of cervix, anogenital, head, and neck tissues. The incidence of these HPV-related squamous neoplasms is markedly increased in the HIV-infected population. Ocular surface squamous neoplasia (OSSN) is also more common in HIV-infected patients. However, the expression pattern of p16 in OSSN among HIV-infected patients is unclear. Here, we examined the expression of p16 in OSSN surgical excisions collected from a large HIV-infected cohort from -Mozambique.

METHODS

OSSN surgical tissue specimens were collected from 75 Mozambican patients. Formalin-fixed, paraffin-embedded tissue blocks from these OSSNs were sectioned, stained with hematoxylin and eosin (H&E), and p16 expression by immunohistochemistry. H&E slides were reviewed to determine if OSSNs were noninvasive conjunctival intraepithelial neoplasms or invasive squamous cell carcinomas (SCC). Cases were classified as p16 positive or negative based on diffuse nuclear and cytoplasmic expression of p16 in neoplastic cells.

RESULTS

p16 positivity was found in a minority of OSSN cases (14/75). p16 positivity was significantly associated with the invasive SCC type of OSSN in HIV-infected patients (p value of 0.026).

CONCLUSIONS

The majority of OSSNs in our HIV-infected cohort do not express p16. However, those cases that are p16-positive are significantly more likely to be the invasive SCC form of OSSN. We propose that p16 expression may identify more aggressive OSSNs in HIV-infected populations.

Inclusion of an E7 DNA Amplification Test Improves the Robustness of Human Papillomavirus-Associated Oropharyngeal Squamous Cell Carcinoma Diagnosis

Background

The rise in human papillomavirus (HPV) infection rates over the last few decades in the USA has contributed to a significant increase in the overall incidence of patients diagnosed with squamous cell carcinoma of the head and neck. These head and neck carcinomas develop in the oropharynx, with more than 90% of them caused by infection with high-risk HPV type 16. Patients diagnosed with HPV-induced oropharyngeal squamous cell carcinomas (OPSCCs) have a better prognosis and treatment response than those diagnosed with head and neck cancers caused by alcohol consumption and tobacco use. To identify patients with HPV-positive OPSCC, new guidelines recommend positive staining of oropharyngeal tissues for p16 INK4a (p16) by immunohistochemistry (IHC). Herein we discuss the testing algorithm that was adopted to address discrepant results between p16 IHC and a DNA in situ hybridization (ISH) test used routinely to diagnose HPV-positive OPSCC patients.

Methods

A DNA polymerase chain reaction (PCR) test that amplifies HPV16 and HPV18 E7 was developed to aid in the diagnosis of HPV-positive OPSCC in a subset of patients. Specimens from these patients stained positive for p16 by an IHC test, but negative for high-risk HPV by a commercial DNA ISH test. Moreover, these results did not match the histopathological characteristics of the specimens, nor the clinical presentations of the patients.

Results

Of 21 patients’ specimens that were tested for p16 by IHC, 11 specimens showed concordant results with the high-risk HPV 16/18 DNA ISH test. Whereas, in eight p16 IHC positive specimens, HPV viral DNA was not detected by HPV16/18 DNA ISH, and two specimens were not tested by DNA ISH. When these eight p16 IHC positive specimens with discrepant p16 IHC and DNA ISH results were further tested by DNA PCR, six specimens showed concordance with p16 IHC with positive results for HPV16 E7, while two specimens were negative for HPV16 E7 by DNA PCR. All tested specimens were negative for HPV18 E7 by DNA PCR. Thus, the addition of the HPV16 and HPV18 E7 DNA PCR test identified a significant number of false negative test results by the HPV16/18 DNA ISH test and likely several false positive results by p16 IHC.

Conclusions

Inclusion of an HPV16 E7 DNA PCR test improved the robustness of HPV-associated OPSCC diagnosis in patients with discrepant results from p16 IHC staining and a DNA ISH test, and identified patients for proper management with less misclassification.

Current Status of p16 Immunohistochemistry and HPV Testing in Fine Needle Aspiration Specimens of the Head and Neck

Human papilloma virus (HPV)-related squamous cell carcinoma (SCC) is biologically unique and has a better prognosis than conventional SCC of the head and neck. p16 immunohistochemistry emerged as a valuable surrogate marker for HPV in oropharyngeal SCC. The criteria for a positive p16 result in tissue specimens are well established. However, there is no consensus regarding interpreting p16 staining in cell blocks and other cytology specimens. This review discusses the current evidence on p16 testing in cytology specimens and also highlights other methods for HPV testing, including DNA and RNA in situ hybridization, as well as other molecular HPV tests.

Smoking and papillomavirus DNA in patients with p16-positive N3 oropharyngeal squamous cell carcinoma

BACKGROUND

We investigated the survival of patients with a p16-positive N3 oropharyngeal squamous cell carcinoma (OPSCC) and the prognostic significance of patient, tumor, and treatment characteristics.

METHODS

We retrospectively reviewed the data of patients treated at our Cancer Center for a p16-positive N3 OPSCC between 2003 and 2016. End points were overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 29 patients were included. The 5-year OS and PFS were 67.5% and 59.1%, respectively. Smoking history above 10 pack-years and the absence of human papillomavirus DNA were associated with worse OS (P = .02 and P = .03, respectively) and PFS (P = .02 and P = .02, respectively). Induction chemotherapy or radical neck dissection were not associated with different treatment outcomes.

CONCLUSION

Patients with an N3 p16-positive oropharyngeal cancer in our series had a 5-year OS rate of 67.5%. Smoking history and viral DNA were prognostic factors associated with survival.

Epstein-Barr virus and human papillomaviruses as favorable prognostic factors in nasopharyngeal carcinoma: A nationwide study in Finland

Background

Nasopharyngeal carcinoma (NPC) is related to Epstein‐Barr virus (EBV) in endemic areas; however, the role of viruses in nonendemic countries is unclear. Our nationwide study investigated the prevalence and prognostic significance of EBV and human papillomaviruses (HPVs) in Finnish NPC tumors.

Methods

We analyzed samples from 150 patients diagnosed between 1990 and 2009. Viral status was determined using EBV and HPV RNA in situ hybridizations, and p16 immunohistochemistry. Patient and treatment characteristics were obtained from patient records.

Results

In our white patient cohort, 93 of 150 (62%) patients were EBV‐positive and 21/150 (14%) patients were HPV‐positive with no coinfections. Thirty‐six (24%) tumors were negative for both viruses. The 5‐year disease‐specific survival for patients with EBV‐positive, HPV‐positive, and EBV/HPV‐negative tumors was 69%, 63%, and 39%, respectively. In multivariable‐adjusted analysis, overall survival was better among patients with EBV‐positive (P = .005) and HPV‐positive (P = .03) tumors compared to patients with EBV/HPV‐negative tumors.

Conclusions

In our low‐incidence population, EBV and HPV are important prognostic factors for NPC.

Unusual Papillary Squamous Cell Carcinoma of the Tip of Tongue Presenting in a Patient Status Post Heart Transplant

Oral papillary squamous cell carcinoma (PSCC) is an unusual variant of squamous cell carcinoma with a better prognosis. The most common location of PSCC in the oral cavity is the gingiva and buccal mucosa, and it is exceedingly rare in the tongue. Herein, we present a case of PSCC in an 85-year-old male with a history of heart transplant and long-term use of immunosuppression medication. A verrucous pedunculated mass measuring 3.5 cm in the greatest dimension was present on the tip of tongue and a partial glossectomy was performed. Histological diagnosis was well differentiated PSCC with focal and minimal stalk invasion. No vascular nor perineural invasion was identified. Based on the current WHO and AJCC oral cancer staging system, the tumor stage was T2N0M0. The tumor cells were focally positive for p16, but in situ hybridization was negative for low-risk HPV (types 6 and 11) and high-risk HPV (types 16, 18, 31, 33 and 51). To the best of our knowledge, this is the first documented case of PSCC present on the tip of tongue in patients with long-term immune suppression. The pathogenesis, stage and prognosis of this entity are discussed. More case studies with long-term follow up are needed to achieve an accurate tumor stage and definite prognosis.

High-risk HPV genotypes and P16INK4a expression in a cohort of head and neck squamous cell carcinoma patients in Singapore

Human papillomavirus (HPV), especially HPV16 genotype, is associated with oropharyngeal squamous cell carcinoma (OPSCC). We aim to determine the prevalence and characterize the high-risk (HR)-HPV genotypes in head and neck SCC (HNSCC) in a South-East Asian multi-ethnic society in Singapore and examine its prognostic significance.159 HNSCC archival tissue samples were retrieved and tumour DNA was screened for 18 HR-HPV genotypes using a PCR-based assay (Qiagen, digene HPV genotyping RH test). P16 protein overexpression was identified using immunohistochemistry (IHC). Statistical correlation between clinical outcomes were performed between HPV-positive and negative HNSCC patients.Six HR-HPVs (HPV16, 18, 31, 45, 56, 68) were detected in 90.6% of HNSCC; and 79.9% had multiple HPV genotypes detected. HPV31 and HPV45 were the most prevalent (79.2% and 87.4%, respectively); and HPV16 was predominantly found in OPSCC (p < 0.001). HPV-DNA PCR assay yielded a high sensitivity (96%) but low specificity (11%) when compared to p16 immunohistochemistry as the reference standard.P16-positive HNSCC was predominantly observed in OPSCC (73.7%; p = 0.005); and p16-positive OPSCC exhibited improved overall survival compared to p16-negative OPSCC (p = 0.022). Similarly, smoking and alcohol consumption were poor prognostic factors of overall survival (p = 0.007; p = 0.01) in OPSCC patients.HR-HPVs were identified in 90.6% of HNSCC patients using the HPV-DNA PCR assay. This test had a poor specificity when compared to p16 IHC; making it an unreliable detection technique in selecting patients for radiation dose de-escalation treatment protocol. P16-positive tumor was predominantly found in the oropharynx these patients demonstrated better overall survival than those with p16-negative OPSCC.

Human papillomavirus and p16 protein expression as prognostic biomarkers in mobile tongue cancer

OBJECTIVES

The objectives were to determine the prevalence of human papillomavirus (HPV) in mobile tongue cancer (MTC) and evaluate associations and survival.

MATERIALS AND METHODS

Patients who underwent surgical resection as primary treatment for MTC (n = 127) were retrospectively evaluated. Formalin-fixed paraffin-embedded (FFPE) specimens were assessed for p16 and p53 by immunohistochemistry; for HPV DNA by nested multiplex polymerase chain reaction (PCR) using two pairs of consensus primers (MY09-MY11 and GP5+-GP6+); and for E6 and E7 oncogenes from 13 high-risk HPV types (16, 18, 31, 33, 35, 39, 45, 52, 56, 58, 59, 66, and 68) by real-time reverse transcription PCR (RT-PCR).

RESULTS

There were 18 (14.2%) p16-positive, 45 (35.4%) p53-positive, 9 (7.1%) HPV DNA-positive, and 7 (5.5%) E6 and/or E7 mRNA-positive tumors, but the correlation of all pairs was poor. There was no demographic or histopathologic association with HPV status. Cause-specific survival was significantly better with p16-positive than with p16-negative tumors (p = .037).

CONCLUSIONS

The prevalence of HPV and p16 positivity was relatively low and p16 status was a poor surrogate marker for HPV status. The results showed the importance of p16 expression in prognosticating mobile tongue cancer.

Using p16 immunohistochemistry to classify morphologic cervical intraepithelial neoplasia 2: correlation of ambiguous staining patterns with HPV subtypes and clinical outcome

p16^INK4a immunohistochemistry (IHC) is widely used to facilitate the diagnosis of human papillomavirus (HPV)-associated cervical precancerous lesions. Although most p16 results are distinctly positive or negative, certain ones are ambiguous: they meet some but not all requirements for the "block-positive" pattern. It is unclear whether ambiguous p16 immunoreactivity indicates oncogenic HPV infection or risk of progression. Herein, we compared HPV genotypes and subsequent high-grade squamous intraepithelial lesion (HSIL) outcomes among 220 cervical biopsies with a differential diagnosis of cervical intraepithelial neoplasia 2 based on hematoxylin and eosin morphology and varying degrees of p16 immunoreactivity. p16 results were classified as block positive (n=40, 18%), negative (n=130, 59%), or ambiguous (n=50, 23%), a category we further grouped into 3 patterns: strong/basal (n=18), strong/focal (n=15), and weak/diffuse (n=17). Seventy percent of ambiguous p16 lesions were negative for the most common low- and high-risk HPV types; the remaining 30% were positive for HPV 16, 18, 45, 58, 59, or 66. Three patterns revealed comparably low HPV detection rates (28%, 27%, and 35%). During 12-month surveillance, HSILs were detected in 35% of the p16 block-positive group, 1.5% of negative group, and 16% of the ambiguous group. The accuracy of ambiguous p16 immunoreactivity in predicting oncogenic HPV and HSIL outcome is significantly lower than that of the block-positive pattern but greater than negative staining. Specific guidelines for this intermediate category should prevent diagnostic errors and help implement p16 IHC in general practice.

HPV-Positive Oropharyngeal Cancer Via p16 Immunohistochemistry in Japan

OBJECTIVES

Human papillomavirus (HPV) has emerged as a driving cause of head and neck cancer, but investigations outside the West are limited. A p16 immunohistochemistry is a commonly used biomarker for HPV cancers. We sought to investigate the pathology and rates of HPV head and neck oropharyngeal cancer in Japan via p16 immunohistochemistry at 2 institutions in Japan.

METHODS

Fifty-nine oropharyngeal specimens from 2 university hospitals in Japan were examined for morphology and p16 immunohistochemistry. The rate of p16 positivity was then determined, and the 2 groups were compared for differences in age, smoking history, gender, and stage of presentation and mortality.

RESULTS

The rate of p16 positivity among the oropharyngeal specimens was 29.5%. There were important differences in the pathology compared to morphology usually seen in the US. The patients with p16+ cancer tended to be younger. There was no significant difference in smoking status. Patients with p16+ cancers trended toward better survival.

CONCLUSION

There appears to be a geographical difference in HPV rates of oropharyngeal cancers with persistently lower rates in Asian countries when compared to Western Europe and the US. Conclusions about HPV head and neck squamous cell carcinoma (HNSCC) in Western countries may not be generalizable across the globe at this time.

p16 immunostaining as a predictor of anal and cervical dysplasia in women attending a sexually transmitted infection clinic

BACKGROUND

Carcinogenesis caused by human papillomavirus (HPV) leads to over-expression of p16 protein. p16 may act as a marker of HPV integration with host genome and serve as a surrogate marker of HPV oncogenesis.

MATERIALS AND METHODS

A single center study of 75 women (35 HIV-positive and 40 HIV-negative women) was conducted. Anal and cervical specimens were obtained for cytology and p16 immunostaining.

RESULTS

The sensitivity of p16 to diagnose anal and cervical dysplasia was 50% and 58.8%, respectively, whereas specificity was 98.6% and 100%, respectively. Positive predictive value for anal and cervical was 75% and 100%, whereas negative predictive value was 95.8% and 89.2%, respectively. A strong relationship between the grade of dysplasia and intensity of p16 immunoscore was observed (Pearson correlation r = 0.666, P < 0.0001 and r = 0.496, P < 0.0001 for anal and cervical, respectively).

CONCLUSION

p16 immunostaining with greater specificity for high-grade lesions may improve the diagnostic accuracy, especially for high-grade lesions which have a high risk of progression to malignancy and thereby necessitate treatment.

Low etiologic fraction for human papillomavirus in larynx squamous cell carcinoma

BACKGROUND

Human Papillomavirus (HPV) is a cause of oropharyngeal squamous cell carcinoma (OPSCC), but its pathogenic role in larynx squamous cell carcinoma (LSCC) remains unclear.

MATERIAL AND METHODS

A single-institutional, retrospective case-series was performed to estimate the etiological fraction (EF) for HPV in LSCC. Eligible cases included 436 consecutive cases of LSCC diagnosed (2005-2014) at The Ohio State University Medical Center. HPV DNA presence was detected by consensus primer PCR (Inno-LiPa) and HPV type-specific qPCR. HPV E6/E7 mRNA expression was detected by type-specific qRT-PCR. Tumor p16 expression was evaluated by immunohistochemistry (IHC).

RESULTS

HPV DNA was detected by Inno-LiPa in 54 of 404 (13.4%, 95% CI 10.2-17.1) evaluable samples but was confirmed by HPV type-specific qPCR in only 14 (3.5%, 95% CI 1.9-5.7). Only 7 of 404 (1.7%, 95% CI 0.7-3.5) LSCC were positive for HPV E6/E7 mRNA expression, including HPV16 (n=4) and 1 each for 11, 26 and 33. In the HPV11-positive tumor, Sanger sequencing discovered 6 nucleotide mutations in the upstream regulation region, E6 and E7. Of 404 LSCC, 18 had strong and diffuse p16 expression. In comparison to a gold standard of HPV E6/E7 mRNA expression, p16 expression had a sensitivity of 71.4% (95% CI 29.0-96.3), specificity of 96.7% (95% CI 94.5-98.3), positive-predictive-value (PPV) of 27.8% (95% CI 9.7-53.5) and negative-predictive-value of 99.5% (95% CI 98.1-99.9).

CONCLUSION

The EF for HPV in LSCC is low (1.7%) in a geographic region with high EF for OPSCC. Low-risk HPV may rarely cause LSCC. Finally, p16 expression has poor PPV for HPV in LSCC.

Nonkeratinizing Squamous Cell Carcinoma In Situ of the Upper Aerodigestive Tract: An HPV-Related Entity

The clinical and pathologic characteristics of human papillomavirus (HPV)-related premalignant lesions in the upper aerodigestive tract have not been adequately studied. There are a few reports of oral cavity HPV-related severe dysplasia with unique morphology (prominent apoptosis/karyorrhexis imparting a 'bowenoid' appearance) and a single case report of HPV-related squamous cell carcinoma in situ with nonkeratinizing histology distinct from the 'bowenoid' pattern that extensively involved the upper aerodigestive tract. The aim of this study was to characterize the morphologic and clinical features of HPV-related severe dysplasia/carcinoma in situ. All cases of upper aerodigestive tract severe dysplasia/carcinoma in situ (111 cases from 98 patients) at Washington University from July 2012 to March 2015 were categorized into histologic types: keratinizing, nonkeratinizing, mixed or 'bowenoid'. There were 83 (85 %) patients with keratinizing, 3 (3 %) nonkeratinizing and 12 (12 %) mixed patterns. The previously reported 'bowenoid' morphology was not identified. All 3 (100 %) nonkeratinizing and 6 (50 %) mixed cases were p16 and HPV RNA in situ hybridization (RNA ISH) positive (100 % concordance between p16 and RNA ISH). Only 2 of 73 keratinizing cases were p16 positive, 1 of which was also HPV RNA ISH positive (1.4 % of keratinizing cases HPV-related). Thus, nonkeratinizing morphology was a strong predictor of transcriptionally-active HPV in severe dysplasia/carcinoma in situ. HPV-related cases most commonly occurred in the floor of mouth and were frequently extensive (≥4 cm) or unresectable.

p16 expression independent of human papillomavirus is associated with lower stage and longer disease-free survival in oral cavity squamous cell carcinoma

There is limited information regarding the incidence of p16 expression, its association with human papillomavirus (HPV) and prognosis in oral cavity squamous cell carcinoma (OSCC). The role of p16 in OSCC is evaluated in 215 cases using tissue microarrays (TMAs). p16 immunohistochemistry and HPV in situ hybridisation were performed on TMAs following histopathology review of 215 patients with OSCC in the Sydney Head and Neck Cancer Institute database. Thirty-seven (17.2%) cases showed p16 expression without association with HPV. p16 expression significantly decreased with increasing pT category (p=0.002). p16 expression was associated with longer disease-specific survival on univariable analysis (p=0.044) but not on multivariable analysis adjusting for depth of invasion. Amongst patients receiving adjuvant radiotherapy, patients with p16 expression had significantly longer disease-free and overall survival. p16 expression was seen in early stage OSCCs and was associated with better survival following surgery and radiotherapy. While not an independent predictor of survival, p16 may mediate its effects by contributing to reduced proliferative capacity, leading to smaller tumour size and lower invasive potential.

Effect of Lower Anogenital Squamous Terminology Recommendations on the Use of p16 Immunohistochemistry and the Proportion of High-Grade Diagnoses in Cervical Biopsy Specimens

OBJECTIVES

The Lower Anogenital Squamous Terminology (LAST) group has recommended that cervical intraepithelial neoplasia (CIN) terminology be replaced by squamous intraepithelial lesion (SIL) terminology, with p16 immunohistochemistry used to separate lesions formerly diagnosed as CIN grade 2 into high-grade SILs (HSILs) and low-grade SILs. This study investigated the impact of these changes on the frequency of p16 testing and the diagnosis of high-grade lesions.

METHODS

Pathology reports for all cervical biopsy specimens in the 1 year before and after the introduction of LAST recommendations (July 2011 to June 2013) were examined.

RESULTS

Before and after the implementation of LAST, 365 (15.4%) of 2,376 cases were diagnosed as high grade (CIN 2/3) vs 486 (17.6%) of 2,761 cases diagnosed as HSILs (P = .0343), and p16 was performed 79 (3.3%) times vs 383 (13.9%) times (P < .0001).

CONCLUSIONS

Immunohistochemistry for p16 increased dramatically as a result of LAST recommendations, and high-grade diagnoses increased.

p16 immunostaining as a predictor of anal and cervical dysplasia in women attending a sexually transmitted infection clinic

BACKGROUND

Carcinogenesis caused by human papillomavirus (HPV) leads to over-expression of p16 protein. p16 may act as a marker of HPV integration with host genome and serve as a surrogate marker of HPV oncogenesis.

MATERIALS AND METHODS

A single center study of 75 women (35 HIV-positive and 40 HIV-negative women) was conducted. Anal and cervical specimens were obtained for cytology and p16 immunostaining.

RESULTS

The sensitivity of p16 to diagnose anal and cervical dysplasia was 50% and 58.8%, respectively, whereas specificity was 98.6% and 100%, respectively. Positive predictive value for anal and cervical was 75% and 100%, whereas negative predictive value was 95.8% and 89.2%, respectively. A strong relationship between the grade of dysplasia and intensity of p16 immunoscore was observed (Pearson correlation r = 0.666, P < 0.0001 and r = 0.496, P < 0.0001 for anal and cervical, respectively).

CONCLUSION

p16 immunostaining with greater specificity for high-grade lesions may improve the diagnostic accuracy, especially for high-grade lesions which have a high risk of progression to malignancy and thereby necessitate treatment.

Expression of p16 and p53 in Intraepithelial Periocular Sebaceous Carcinoma

PURPOSE

Identifying intraepithelial sebaceous carcinoma cells in small periocular biopsies can be difficult, particularly in the conjunctiva. The goal of this study was to evaluate p53 and p16 immunohistochemistry as potential markers of intraepithelial sebaceous carcinoma.

PROCEDURES

A total of 25 tumors, including 4 recurrent lesions, were stained for p16 and p53, with intensity scored as negative, weak, moderate or strong.

RESULTS

Expression of p16 was detected in intraepithelial sebaceous carcinoma cells in 24 of the 25 cases (96%), with only 1 case showing weak immunoreactivity. Intraepithelial p53 immunoreactivity was present in 17 of 25 tumors (68%), but was weak in 3 cases. Expression levels remained relatively stable in primary and recurrent tumors, but varied in a few cases between intraepithelial and subepithelial sites.

CONCLUSIONS

Intraepithelial sebaceous carcinomas stained for p53 and p16 demonstrated moderate to strong immunoreactivity in 100% of cases for at least one of these proteins, suggesting that together they are useful markers for determining the extent of tumor spread. Of the two, p16 was immunoreactive in more cases than p53.

HPV-related Oropharyngeal Squamous Cell Carcinoma: p16INK4A Immunohistochemistry or HPV Genotyping?

BACKGROUND

Infection with high-risk human papillomavirus (HPV) is linked to a sub-group of squamous cell oropharyngeal tumors (OPSCC). Our aim was to compare an HPV Polymerase Chain Reaction (PCR) assay and p16(INK4A) expression status by immunohistochemistry (IHC) as a surrogate marker.

MATERIALS AND METHODS

This was a retrospective study considering patients affected by squamous cell oropharyngeal tumors. All included samples were processed for IHC for p16(INK4A) and tested by PCR for detection of HPV DNA and HPV genotyping.

RESULTS

A total of 84 patients affected by squamous cell oropharyngeal tumors were included and tested. A significant positive correlation was found between HPV PCR and p16(INK4A) IHC but the agreement was poor (k coefficient of 0.25). In fact, the sensitivity of p16(INK4A) IHC positivity in detecting HPV PCR positivity was low (28.21%, 95% confidence interval=16.54% - 43.78%).

CONCLUSION

Positivity of p16(INK4A) by IHC had a low sensitivity in detecting HPV DNA and our results suggest the need at least to test p16(INK4A) IHC- negative samples using HPV PCR to increase detection accuracy and provide valuable information for the clinical management of these patients.

Detection of human papillomavirus (HPV) in clinical samples: evolving methods and strategies for the accurate determination of HPV status of head and neck carcinomas

Much recent attention has highlighted a subset of head and neck squamous cell carcinomas (HNSCCs) related to human papillomavirus (HPV) that has an epidemiologic, demographic, molecular and clinical profile which is distinct from non-HPV-related HNSCC. The clinical significance of detecting HPV in a HNSCC has resulted in a growing expectation for HPV testing of HNSCCs. Although the growing demand for routine testing is understandable and appropriate, it has impelled an undisciplined approach that has been largely unsystematic. The current state of the art has now arrived at a point where a better understanding of HPV-related tumorigenesis and a growing experience with HPV testing can now move wide scale, indiscriminant and non-standardized testing towards a more directed, clinically relevant and standardized approach. This review will address the current state of HPV detection; and will focus on why HPV testing is important, when HPV testing is appropriate, and how to test for the presence of HPV in various clinical samples. As no single test has been universally accepted as a best method, this review will consider the strengths and weaknesses of some of the more commonly used assays, and will emphasize some emerging techniques that may improve the efficiency of HPV testing of clinical samples including cytologic specimens.

Anal cytology and p16 immunostaining for screening anal intraepithelial neoplasia in HIV-positive and HIV-negative men who have sex with men: a cross-sectional study

Summary Akin to cervical cancer in sexually-active women, men who have sex with men (MSM) are predisposed to anal cancers, especially those with HIV co-infection. This cross-sectional study endeavored to assess the prevalence of anal dysplasia using Pap smears and p16 immunostaining amongst Indian MSM. A total of 31 consecutive HIV-positive and 34 HIV-negative MSM, from a cohort of sexually transmitted infection clinic attendees, underwent anal cytological evaluation with Pap smear and p16 staining. Chi square test and coefficient of correlation were used for comparison. Eighteen (27.7%) had abnormal anal cytology; increased in HIV-positive as compared to HIV-negative men (35% versus 20%, p = 0.180). Similarly, both low-grade (25.8% versus 17.6%) and high-grade lesions (8.3% versus 4.8%) were comparable in HIV-positive and HIV-negative group. Thirteen (20%) smears were p16-positive with a sensitivity and specificity for anal dysplasia of 72.3% and 100%, respectively. Anal cytology may be used to screen for anal dysplasia in MSM irrespective of HIV status. Furthermore, the addition of p16, with greater specificity for high-grade lesions, may improve diagnostic accuracy especially for high-grade lesions. A larger study to further corroborate these observations is warranted.

Human papillomavirus and oropharyngeal cancer in Greenland in 1994-2010

Background

Oropharyngeal squamous cell carcinoma (OPSCC) is associated with the sexually transmitted human papillomavirus (HPV), smoking and alcohol. In Greenland, a high rate of HPV-induced cervical cancer and venereal diseases are found, which exposes the population for high risk of HPV infection. In Greenland, only girls are included in the mandatory HPV vaccination program.

Objective

To investigate the annual incidence of OPSCC and the proportion of HPV-associated OPSCC (HPV+ OPSCC) in Greenland in 1994–2010.

Design

At Rigshospitalet, University of Copenhagen, we identified all Greenlandic patients diagnosed and treated for OPSCC from 1994 to 2010. Sections were cut from the patient's paraffin-embedded tissue blocks and investigated for p16 expression by immunohistochemistry. HPV analyses were performed with 2 sets of general HPV primers and 1 set of HPV16-specific primer. HPV+ OPSCC was defined as both >75% p16+ cells and PCR positive for HPV.

Results

Of 26 Greenlandic patients diagnosed with OPSCC, 17 were males and 9 were females. The proportion of HPV+ OPSCC in the total study period was 22%, without significant changes in the population in Greenland. We found an increase in the proportion of HPV+ OPSCC from 14% in 1994–2001 to 25% in 2002–2010 (p=0.51). Among males from 20 to 27% (p=0.63) and in females from 0 to 20% (p=0.71). The annual OPSCC incidence increased from 2.3/100,000 (CI=1.2–4.2) in 1994–2001 to 3.8/100,000 (CI=2.4–6.2) in 2002–2010: among males from 2.4/100,000 (CI=1.0–5.7) to 5.0/100,000 (CI=2.9–8.9).

Conclusion

Even though the population is at high risk of HPV infection, the proportion of 22% HPV+ OPSCC in the total study period is low compared to Europe and the United States. This might be explained by our small study size and/or by ethnic, geographical, sexual and cultural differences. Continuing observations of the OPSCC incidence and the proportion of HPV+ OPSCC in Greenland are needed.

Spindle cell carcinomas of the head and neck rarely harbor transcriptionally-active human papillomavirus

Spindle cell carcinoma is an uncommon variant of squamous cell carcinoma characterized by spindled or pleomorphic cells which appear to be a true sarcoma but are actually epithelial. Some head and neck squamous cell carcinoma variants can be human papillomavirus (HPV)-related and have improved outcomes. We sought to determine if spindle cell carcinomas are associated with transcriptionally-active HPV. Cases of spindle cell carcinoma were retrieved from department files. Transcriptionally-active HPV was determined by mRNA in situ hybridization for high risk HPV E6 and E7 transcripts and by a surrogate marker, p16 immunohistochemistry, with a 50% staining cutoff. RT-PCR for high risk HPV mRNA was performed on the cases that were technical failures by in situ hybridization. Medical records and follow up information were retrieved for all patients. Of 31 cases, 5 were from the oropharynx, 12 from the oral cavity, and 14 from the larynx or hypopharynx. One purely spindled oral cavity spindle cell carcinoma was HPV positive. It was also diffusely positive for p16. Another laryngeal spindle cell carcinoma was HPV positive in both the squamous and spindle cell components, but was negative for p16. None of the five oropharyngeal spindle cell carcinomas were positive for p16 or HPV RNA. The HPV positive patients both presented at high stage (IV) and died with disease within 2 years of diagnosis. The majority of spindle cell carcinomas of the head and neck, including those arising in the oropharynx, are not related to transcriptionally active HPV. Although the number of cases is too small for any definitive conclusions, for the rare HPV positive spindle cell carcinoma cases, positive viral status does not appear to confer any prognostic benefit.

p16 Immunohistochemistry as a standalone test for risk stratification in oropharyngeal squamous cell carcinoma

It is widely acknowledged that human papillomavirus (HPV)-related oropharyngeal carcinoma is a biologically unique form of head and neck cancer that should be singled out and treated differently. It is now incumbent to find a test (or combination of tests) that accurately identifies cancers with the associated favorable prognosis for proper patient counseling and management and for placing patients in the correct treatment arms in the emerging clinical trials that are attempting to establish unique treatment types and approaches. The test (or combination of tests) that are utilized must be widely available, reliable, easy to interpret, and well-validated. While HPV-specific testing seems completely logical to use as a single test or one of a combination of tests, it turns out to be quite complicated in practice. Because of the different forms of the virus, the differing types of HPV-specific tests can give different information. HPV DNA, RNA, and protein assays have varying sensitivities for virus detection and also varying availability from formalin-fixed, paraffin-embedded tissue. Since p16 protein over expression is very sensitive for the presence of transcriptionally-active HPV and since it correlates strongly with patient outcomes, is widely available, and easy to interpret, it appears to currently be the single test that combines all of the desired attributes in a risk stratification marker for widespread implementation in clinical and research study settings. This article will review the literature on p16 immunohistochemistry and its relation to HPV-specific testing, discuss some practical issues related to its implementation, and present the case for why it should be the single test used for this purpose.

Introduction: Human papillomavirus in head and neck cancer: an update for 2012 with a focus on controversial topics

Human papillomavirus has emerged as a major pathogen, capable of causing cancer at many different sites. In the head and neck, human papillomavirus is associated with many squamous cell carcinomas and is particularly important in the oropharynx. This is a fast moving topic with many important epidemiological, biological, pathological, and clinical features that are often confusing and misunderstood. This article introduces a series of timely reviews and editorials on this important subject in head and neck oncology.

Small biopsy specimens reliably indicate p16 expression status of oropharyngeal squamous cell carcinoma

Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (SCC) is associated with favorable patient survival. Tumor HPV status at primary diagnosis is critical for proper management, and p16 immunohistochemistry (IHC) has emerged as a reliable, single, surrogate marker. It is not known, however, if small biopsy specimens are completely adequate for p16 evaluation. From a database of oropharyngeal SCC for which p16 IHC and histologic typing were already performed, all patients (32) who had available in-house primary tumor biopsy specimens and also subsequent surgical resections were analyzed. p16 IHC was performed along with histologic typing into: Type 1 keratinizing SCC, Type 2 nonkeratinizing SCC with maturation, and Type 3 nonkeratinizing SCC. Staining was graded on both biopsies and resections as follows: 0=negative; 1+ =1-25% of tumor cells positive; 2+ =26-50%; 3+ =51-75%; 4+ =76-100%. Strictly considering p16 score, perfect biopsy-resection correlation was present in 28 of 32 cases (85%), including 6/9 (67%) Type 1, 6/7 (86%) Type 2, and 16/16 (100%) Type 3 cases. Considering p16 expression binarily as 51% tumor cell staining or more (3+ or 4+) being positive and lesser amounts (0, 1+, or 2+) as being negative, there was perfect biopsy-resection correlation for all 32 cases. With p16 expression in resection specimens considered the gold standard, p16 IHC in biopsies was both 100% sensitive and specific. Our results demonstrate that p16 staining in diagnostic biopsies reliably reflects whole tumor staining results, and suggest that biopsies do not suffer from false negatives or positives.