ROC analysis of p16 expression in cell blocks of metastatic head and neck squamous cell carcinoma

High-risk human papillomavirus testing in cytology aspiration samples from the head and neck part 1: a review of the literature on available testing options

Human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma is increasing in incidence and is often first diagnosed on a cytology fine needle aspiration (FNA) specimen of metastatic nodal disease of the neck. In the setting of oropharyngeal squamous cell carcinoma, HPV status defines the disease with HPV-associated tumors having better overall prognosis than those that are HPV negative. Furthermore, metastatic squamous cell carcinoma of the neck of unknown origin requires testing for HPV as a positive result suggests an oropharyngeal primary. As a result, HPV testing in aspirate samples is increasingly important for the proper diagnosis and treatment of patients with head and neck squamous cell carcinoma. Although HPV testing in cervicovaginal cytology specimens is common and well-established, testing in head and neck FNA samples remains challenging. p16 immunohistochemistry is an excellent surrogate marker for HPV in tumors of known or suspected oropharyngeal origin, but the criteria used in histologic specimens may not be appropriate in cytology samples. FNA samples are more frequently hypocellular, and cytology cell blocks have variable fixation and processing steps, limiting the utility of p16 immunohistochemistry. Other potential testing options have been reported in the literature including staining of aspirate smears and molecular testing of liquid-based samples. The American Society of Cytopathology Clinical Practice Committee recently surveyed the American Society of Cytopathology membership to determine the current state of HPV testing in aspirate samples, and this review article is designed to provide a summary of the current literature on various testing options in FNA samples.

Tumor Cell Extrinsic Synaptogyrin 3 Expression as a Diagnostic and Prognostic Biomarker in Head and Neck Cancer

Over 70% of oropharyngeal head and neck squamous cell carcinoma (HNSC) cases in the United States are positive for human papillomavirus (HPV) yet biomarkers for stratifying oropharyngeal head and neck squamous cell carcinoma (HNSC) patient risk are limited. We used immunogenomics to identify differentially expressed genes in immune cells of HPV(+) and HPV(-) squamous carcinomas. Candidate genes were tested in clinical specimens using both quantitative RT-PCR and IHC and validated by IHC using the Carolina Head and Neck Cancer Study (CHANCE) tissue microarray of HNSC cases. We performed multiplex immunofluorescent staining to confirm expression within the immune cells of HPV(+) tumors, receiver operating characteristic (ROC) curve analyses, and assessed survival outcomes. The neuronal gene Synaptogyrin-3 (SYNGR3) is robustly expressed in immune cells of HPV(+) squamous cancers. Multiplex immunostaining and single cell RNA-seq analyses confirmed SYNGR3 expression in T cells, but also unexpectedly in B cells of HPV(+) tumors. ROC curve analyses revealed that combining SYNGR3 and p16 provides more sensitivity and specificity for HPV detection compared to p16 IHC alone. SYNGR3-high HNSC patients have significantly better prognosis with five-year OS and DSS rates of 60% and 71%, respectively. Moreover, combining p16 localization and SYNGR3 expression can further risk stratify HPV(+) patients such that high cytoplasmic, low nuclear p16 do significantly worse (Hazard Ratio, 8.6; P = 0.032) compared to patients with high cytoplasmic, high nuclear p16. SYNGR3 expression in T and B cells is associated with HPV status and enhanced survival outcomes of HNSC patients.

Concordance of p16INK4a and E6*I mRNA among HPV-DNA-Positive Oropharyngeal, Laryngeal, and Oral Cavity Carcinomas from the ICO International Study

Background: Tests or test algorithms for diagnosing HPV-driven oral cavity and laryngeal head and neck carcinomas (HNC) have not been yet validated, and the differences among oral cavity and laryngeal sites have not been comprehensively evaluated. We aimed to assess the utility of a diagnostic algorithm for the detection of HPV-driven oral cavity (OCC), oropharyngeal (OPC) and laryngeal (LC) carcinomas using HPV-DNA testing followed by p16INK4a immunohistochemistry, taking E6*I mRNA detection as the reference standard. Methods: Formalin-fixed paraffin-embedded OCC, OPC, and LC carcinomas were collected from pathology archives in 29 countries. All samples were subjected to histopathological evaluation, DNA quality control, and HPV-DNA detection. All HPV-DNA-positive samples (including 78 OCC, 257 OPC, and 51 LC out of 3680 HNC with valid HPV-DNA results) were also tested for p16INK4a immunohistochemistry and E6*I mRNA. Three different cutoffs of nuclear and cytoplasmic staining were evaluated for p16INK4a: (a) >25%, (b) >50%, and (c) ≥70%. The concordance of p16INK4a and E6*I mRNA among HPV-DNA-positive OCC, OPC, and LC cases was assessed. Results: A total of 78 OCC, 257 OPC, and 51 LC were HPV-DNA-positive and further tested for p16INK4a and E6*I mRNA. The percentage of concordance between p16INK4a (cutoff ≥ 70%) and E6*I mRNA among HPV-DNA-positive OCC, OPC, and LC cases was 79.5% (95% CI 69.9−89.1%), 82.1% (95% CI 77.2−87.0%), and 56.9% (95% CI 42.3−71.4%), respectively. A p16INK4a cutoff of >50% improved the concordance although the improvement was not statistically significant. For most anatomical locations and p16INK4a cutoffs, the percentage of discordant cases was higher for HPV16- than HPV-non16-positive cases. Conclusions: The diagnostic algorithm of HPV-DNA testing followed by p16INK4a immunohistochemistry might be helpful in the diagnosis of HPV-driven OCC and OPC, but not LC. A different p16INK4a expression pattern was observed in those cases HPV-DNA-positive for types other than HPV16, as compared to HPV16-positive cases. Our study provides new insights into the use HPV-DNA, p16INK4a, and HPV-E6*I mRNA for diagnosing an HPV-driven HNC, including the optimal HPV test or p16INK4a cutoffs to be used. More studies are warranted to clarify the role of p16INK4a and HPV status in both OPC and non-OPC HNC.

Detection accuracy of the Cobas HPV assay for high-risk HPV in head and neck FNA biopsy specimens

BACKGROUND

This study evaluated the detection accuracy of the Cobas human papillomavirus (HPV) assay for high-risk human papillomavirus (hrHPV) and HPV-16 in head and neck fine-needle aspiration (FNA) specimens with squamous cell carcinoma.

METHODS

Head and neck FNA biopsy specimens from 2012 to 2020 were retrospectively collected. Cobas HPV testing was performed on 90 FNA specimens with valid Cervista HPV testing results. Results of Cobas HPV and Cervista HPV assays were compared. A Linear Array or SPF10-LiPA25 HPV genotyping assay resolved cases with discrepant results. The κ value and accuracy of Cobas HPV testing were calculated. The accuracy of the Cobas HPV assay was also determined in 42 FNA needle-rinse specimens.

RESULTS

Cobas HPV was positive in 82% of the FNA specimens (74 of 90). The concordance between Cobas HPV and Cervista HPV test results was 88.9% (80 of 90) with substantial agreement (κ = 0.669; 95% CI, 0.481-0.856). With HPV genotyping confirmation in cases with discrepant results between the 2 HPV assays, Cobas HPV showed 100% sensitivity and specificity for hrHPV. HPV-16 was detected in 88% of HPV-positive cases (65 of 74). HPV genotyping confirmed 1 false-negative HPV-16 result and 1 false-positive HPV-16 result. Overall, the accuracy of Cobas HPV for HPV-16 was 97.8%. The accuracy of Cobas HPV in FNA needle-rinse specimens was 100%.

CONCLUSIONS

The Cobas HPV assay is highly accurate for determining the HPV status in head and neck FNA specimens. FNA needle rinse is valid for Cobas HPV testing in patients with squamous cell carcinoma.

Validation of p16 immunocytochemical staining on alcohol-fixed aspirate smears: A single-institutional study with review of the literature

BACKGROUND

Determining human papillomavirus (HPV) status in oropharyngeal squamous cell carcinoma can have a significant impact on treatment and clinical outcomes. Because fine-needle aspiration (FNA) is typically an initial diagnostic modality in a patient workup for primary or suspected metastatic disease, immunostaining for p16 on FNA material is a promising option to determine HPV tumor status, possibly avoiding biopsies or excisions. In this study, the authors investigated the possibility of using alcohol-fixed smears as a reliable alternative for reporting p16 status.

METHODS

Twenty HPV-associated tumors and 20 non-HPV-associated tumors were identified using the gold-standard histologic cutoff for positivity of ≥70% strong nuclear and cytoplasmic staining. Matched FNA specimens were identified for comparison staining, and a positive p16 result was rendered on a single aspirate smear using the same cutoff of ≥70%.

RESULTS

On alcohol-fixed cytology smears, 16 of 20 (80%) HPV-associated tumors showed positive p16 staining in ≥70% tumor cells. Four cases showed lower level (30%-60%) nuclear and cytoplasmic staining. Nineteen of 20 (95%) non-HPV-associated tumors showed no or minimal p16 staining (0%-10%), and 1 case had a p16-equivocal cytology result.

CONCLUSIONS

The authors performed immunocytochemical validation for p16 using alcohol-fixed smears and observed promising results, offering this technique as a potential alternative to formalin-fixed tissue in the appropriate clinical context. By using a positive staining cutoff of ≥70%, this technique offers 80% sensitivity and 95% specificity for detecting HPV-associated tumors. Although it was not performed in the current study, HPV-specific testing on available formalin-fixed, paraffin-embedded tissue should be considered in cases with equivocal or negative p16 staining.

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.