Clinical and Molecular Characterization of Surgically Treated Oropharynx Squamous Cell Carcinoma Samples

p16 and p53 can Serve as Prognostic Markers for Head and Neck Squamous Cell Carcinoma

OBJECTIVE

The present study aimed to explore the expression and clinical significance of human papilloma virus-related pathogenic factors (p16, cyclin D1, p53) in patients with head and neck squamous cell carcinoma (HNSCC) and construct a predictive model.

METHODS

The Cancer Genome Atlas was used to obtain clinical data for 112 patients with HNSCC. Expression of p16, p53, and cyclin D1 was quantified. We used the survival package of the R program to set the cut-off value. Values above the cut-off were considered positive, while values below the cut-off were negative. Kaplan-Meier analysis and univariate and multivariate Cox regression analyses were performed to investigate prognostic clinicopathological indicators and the expression of p16, p53, and cyclin D1. A predictive model was constructed based on the results of multifactor Cox regression analysis, and the accuracy of the predictive model was verified through final calibration analysis. Follow-up of patients with HNSCC at the Affiliated Hospital of Binzhou Medical University was conducted from 2015 to 2017, and reliability of the predictive model was validated based on follow-up data and molecular expression levels.

RESULTS

According to the results, expression of p16 and p53 was significantly associated with prognosis (P < .05). The predictive model constructed based on the expression levels of p16 and p53 was useful for evaluating the prognosis of patients with HNSCC. The predictive model was validated using follow-up data obtained from the hospital, and the trend of the follow-up results was consistent with the predictive model.

CONCLUSION

p16 and p53 can be used as key indicators to predict the prognosis of HNSCC patients and as critical immunohistochemical indicators in clinical practice. The survival model constructed based on p16 and p53 expression levels reliably predicts patient prognosis.

LINE-1 hypomethylation is associated with poor outcomes in locoregionally advanced oropharyngeal cancer

BACKGROUND AND PURPOSE

Currently, human papillomavirus (HPV) positivity represents a strong prognostic factor for both reduced risk of relapse and improved survival in patients with oropharyngeal squamous cell carcinoma (OPSCC). However, a subset of HPV-positive OPSCC patients still experience poor outcomes. Furthermore, HPV-negative OPSCC patients, who have an even higher risk of relapse, are still lacking suitable prognostic biomarkers for clinical outcome. Here, we evaluated the prognostic value of LINE-1 methylation level in OPSCC patients and further addressed the relationship between LINE-1 methylation status and p53 protein expression as well as genome-wide/gene-specific DNA methylation.

RESULTS

In this study, DNA was extracted from 163 formalin-fixed paraffin-embedded tissue samples retrospectively collected from stage III-IVB OPSCC patients managed with curative intent with up-front treatment. Quantitative methylation-specific PCR revealed that LINE-1 hypomethylation was directly associated with poor prognosis (5-year overall survival-OS: 28.1% for LINE-1 methylation < 35% vs. 69.1% for ≥ 55%; p < 0.0001). When LINE-1 methylation was dichotomized as < 55% versus ≥ 55%, interaction with HPV16 emerged: compared with hypermethylated HPV16-positive patients, subjects with hypomethylated HPV16-negative OPSCC reported an adjusted higher risk of death (HR 4.83, 95% CI 2.24-10.38) and progression (HR 4.54, 95% CI 2.18-9.48). Tumor protein p53 (TP53) gene is often mutated and overexpressed in HPV-negative OPSCC. Since p53 has been reported to repress LINE-1 promoter, we then analyzed the association between p53 protein expression and LINE-1 methylation levels. Following p53 immunohistochemistry, results indicated that among HPV16-negative patients with p53 ≥ 50%, LINE-1 methylation levels declined and remained stable at approximately 43%; any HPV16-positive patient reported p53 ≥ 50%. Finally, DNA methylation analysis demonstrated that genome-wide average methylation level at cytosine-phosphate-guanine sites was significantly lower in HPV16-negative OPSCC patients who relapsed within two years. The subsequent integrative analysis of gene expression and DNA methylation identified 20 up-regulated/hypomethylated genes in relapsed patients, and most of them contained LINE-1 elements in their promoter sequences.

CONCLUSIONS

Evaluation of the methylation level of LINE-1 may help in identifying the subset of OPSCC patients with bad prognosis regardless of their HPV status. Aberrant LINE-1 hypomethylation might occur along with TP53 mutations and lead to altered gene expression in OPSCC.

Relevance of Human Papillomaviruses in Head and Neck Cancer-What Remains in 2021 from a Clinician's Point of View?

Human papillomaviruses (HPV) cause a subset of head and neck cancers (HNSCC). HPV16 predominantly signs responsible for approximately 10% of all HNSCC and over 50% of tonsillar (T)SCCs. Prevalence rates depend on several factors, such as the geographical region where patients live, possibly due to different social and sexual habits. Smoking plays an important role, with non-smoking patients being mostly HPV-positive and smokers being mostly HPV-negative. This is of unparalleled clinical relevance, as the outcome of (non-smoking) HPV-positive patients is significantly better, albeit with standard and not with de-escalated therapies. The results of the first prospective de-escalation studies have dampened hopes that similar superior survival can be achieved with de-escalated therapy. In this context, it is important to note that the inclusion of p16^INK4A (a surrogate marker for HPV-positivity) in the 8th TMN-classification has only prognostic, not therapeutic, intent. To avoid misclassification, highest precision in determining HPV-status is of utmost importance. Whenever possible, PCR-based methods, still referred to as the "gold standard”, should be used. New diagnostic antibodies represent some hope, e.g., to detect primaries and recurrences early. Prophylactic HPV vaccination should lead to a decline in HPV-driven HNSCC as well. This review discusses the above aspects in detail.

Oropharyngeal squamous cell carcinoma: p16/p53 immunohistochemistry as a strong predictor of HPV tumour status

AIMS

Oropharyngeal squamous cell carcinomas (OPSCC) related to human papillomavirus (HPV) infection have a better prognosis than those without HPV infection. Although p16^INK4a overexpression is used as a surrogate marker for HPV infection, 5-20% of p16-positive OPSCC are described as being unrelated to HPV infection, with worse overall survival compared to OPSCC-related HPV. There is therefore a risk of undertreating a proportion of OPSCC patients falsely considered to be HPV-driven because of p16 positivity. TP53 mutations are highly prevalent in OPSCC driven by mutagens in tobacco and alcohol. We describe herein a combined p16/p53 algorithm to predict HPV tumour status in OPSCC.

METHODS AND RESULTS

A total of 110 OPSCC were identified in the database of the pathology department and were studied using p16 and p53 immunohistochemistry. For p16-positive or p16-negative/wild-type patterns-p53 (WT-p53) cases (n = 63), DNA in-situ hybridisation for high-risk HPV was performed, and if negative the HPV status was controlled by HPV DNA polymerase chain reaction (PCR) (n = 19). A significant association between TP53 mutation and pattern of p53 expression was found (WT-p53, seven of 16, P < 0.001). The p16-positive/WT-p53 was significantly associated with HPV⁺ tumour status (p16-positive/WT-p53, 50 of 110, P < 0.001). Interestingly, a subset of p16-positive OPSCC was unrelated to HPV (13.5%, eight of 59), and showed mutant-type staining of p53 expression.

CONCLUSIONS

The p16 protein immunopositivity in conjunction with the mutant-type pattern of p53 staining helped to reclassify a subset of p16-positive OPSCC as OPSCC-unrelated HPV. This approach could be routinely applied by pathologists involved in the management of OPSCC, because of their potential therapeutic implications.

Human Papillomavirus DNA Detection by Droplet Digital PCR in Formalin-Fixed Paraffin-Embedded Tumor Tissue from Oropharyngeal Squamous Cell Carcinoma Patients

INTRODUCTION

High-risk human papillomavirus infection impacts staging and prognosis of oropharyngeal squamous cell carcinomas (OPSCCs). Determination of HPV status in tumor tissue by p16-immunohistochemistry (p16-IHC) can be challenging; therefore, complementary methodologies could be useful in a clinical setting.

OBJECTIVE

To test for accuracy and clinical relevance of HPV-DNA detection in formalin-fixed and paraffin-embedded (FFPE) tumor samples by droplet digital PCR (ddPCR).

MATERIALS AND METHODS

Fifty OPSCCs were tested for p16-IHC status followed by HPV-16/18 DNA detection/quantification in FFPE-recovered DNA using ddPCR. Accuracy for HPV status determination and association with patient information were also evaluated.

RESULTS

32.0% (16/50) of the cases were p16-IHC positive (p16 +), 42.0% (21/50) had detectable levels of HPV-16 DNA, and none were positive for HPV-18 DNA. A higher median viral load of HPV-16 DNA was observed in p16 + cases (p < 0.0001). Concordance between p16-IHC and HPV-16 DNA ranged from 78.0 to 86.0% and accuracy rates were between 78.0 and 86.0%. P16-IHC and HPV-16 DNA detection was associated with gender, smoking status, and tumor subsite, while only HPV-16 DNA was associated with cT stage. The combination of HPV positivity by p16-IHC and ddPCR showed higher overall survival rates in comparison with p16 + /HPV-DNA- and p16 - /HPV-DNA- results.

CONCLUSIONS

Type-specific HPV-DNA detection by ddPCR is highly specific but moderately sensitive for the determination of HPV status and showed clinical relevance, mainly when associated with p16-IHC status. Results highlight the importance of performing HPV-DNA testing in combination with p16-IHC for proper identification of HPV-associated OPSCC and to improve clinical management of OPSCC patients.

Prevalence of p16 expression in oropharyngeal squamous cell carcinoma in southern Brazil

OBJECTIVE

Our aim was to evaluate the prevalence of human papillomavirus (HPV)-positive tumors in a cohort of patients with oropharyngeal squamous cell carcinoma (OPSCC) at a single center in southern Brazil and determine the short-term prognostic factors in this sample.

STUDY DESIGN

Ninety-one consecutive patients with newly diagnosed primary OPSCC between January 2017 and December 2019 were retrospectively included. Demographic, clinical, pathologic, and survival data were collected. HPV status was determined by using p16 immunohistochemistry.

RESULTS

The overall prevalence of HPV-positive (HPV+) OPSCC was 20.9%. Patients with HPV+ tumors presented a nodal metastasis as the first clinical sign (P = .02); reported less alcohol (P < .001) and tobacco use (P < .001); exhibited lower tumor stages (P < .001) and higher microscopic grades (P = .01); and had higher chances of having resectable tumors (P = .008). p16-negative status (P = .01); unresectable/inoperable tumors (P < .001); presence of nodal metastasis (P = .005); and higher American Joint Committee on Cancer (AJCC) stage (P = .002) were significantly associated with worse disease-specific survival.

CONCLUSIONS

The prevalence of HPV+ OPSCC in southern Brazil is relatively low, and p16-positive status was associated with Better prognosis. Higher AJCC stage, nodal metastasis, and unresectability/inoperability were associated with the highest hazard ratios for death resulting from OPSCC.

TERT Promoter Mutation C228T Increases Risk for Tumor Recurrence and Death in Head and Neck Cancer Patients

Background: Head and neck squamous cell carcinoma (HNSCC) is usually associated to tobacco and alcohol consumption. Increased telomerase activity has been consistently detected in 80–90% of malignant tumors, including HNSCC. Mutations within the promoter region of telomerase reverse transcriptase (TERT) that confer enhanced TERT promoter activity have been reported in two major hotspots, designated C228T and C250T.

Objectives: To evaluate TERT promoter mutations C228T and C250T in HNSCC patients from Brazil and correlate with patients' outcome.

Materials and Methods: Formalin-fixed paraffin-embedded tissues were obtained from 88 HNSCC patients and analyzed for TERT promoter mutations C228T and C250T by pyrosequencing.

Results: The overall prevalence of hotspot TERT mutations in HNSCC samples was of 27.3%, with 6.8% at locus C228T and 20.5% at C250T. The majority (92%) of mutated cases were located in oral cavity, mainly at the tongue. We observed that 94.4% of the patients harboring TERT promoter mutation C250T were alcohol consumers (p = 0.032) and 66.7% of the patients harboring TERT promoter mutation C228T were not alcohol consumers (p = 0.035). The presence of C228T mutation impacted patient outcome, with a significant decrease in disease-free survival (20.0 vs. 63.0%, p =0.017) and in overall survival (16.7 vs. 45.1%, p = 0.017).

Conclusion: This is the first report of a TERT promoter mutations in HNSCC patients from South America. The high prevalence of TERT mutation, as well as its association with poor disease-free survival and overall survival, particular at C228T locus might serve as a prognostic biomarker in HNSCC to help clinicians in the management of treatment.

Feasibility of methylated ctDNA detection in plasma samples of oropharyngeal squamous cell carcinoma patients

BACKGROUND

Oropharyngeal squamous cell carcinomas (OpSCCs) are commonly associated with high rates of treatment failure.

OBJECTIVES

To evaluate methylation-based markers in plasma from OpSCC patients as emerging tools for accurate/noninvasive follow-up.

METHODS

Pretreatment formalin-fixed paraffin-embedded (FFPE) biopsies (n = 52) and paired plasma (n = 15) were tested for the methylation of CCNA1, DAPK, CDH8, and TIMP3 by droplet digital PCR (ddPCR).

RESULTS

Seventy-one percent (37/52) of the biopsies showed methylation of at least one of the evaluated genes and tumor CCNA1 methylation was associated with recurrence-free survival. Methylated circulating tumor DNA (meth-ctDNA) was detected in 11/15 (73.3%) plasma samples; conversely, plasma samples from healthy controls were all negative for DNA methylation (area under the curve = 0.867; 95% confidence interval = 0.720-1.000). Additionally, preliminary results on the detection of meth-ctDNA in plasma collected during follow-up closely matched patient outcome.

CONCLUSIONS

The results suggest the feasibility of detecting meth-ctDNA in plasma using ddPCR and a possible application on routine setting after further validation.

Impact of genetic variants in clinical outcome of a cohort of patients with oropharyngeal squamous cell carcinoma

Tobacco- or human papillomavirus- driven oropharyngeal squamous cell carcinomas (OpSCC) represent distinct clinical, biological and epidemiological entities. The aim of this study was to identify genetic variants based on somatic alterations in OpSCC samples from an admixed population, and to test for association with clinical features. The entire coding region of 15 OpSCC driver genes was sequenced by next-generation sequencing in 51 OpSCC FFPE samples. Thirty-five percent of the patients (18/51) were HPV-positive and current or past tobacco consumption was reported in 86.3% (44/51). The mutation profile identified an average of 2.67 variants per sample. Sixty-three percent of patients (32/51; 62.7%) were mutated for at least one of the genes tested and TP53 was the most frequently mutated gene. The presence of mutation in NOTCH1 and PTEN, significantly decreased patient's recurrence-free survival, but only NOTCH1 mutation remained significant after stepwise selection, with a risk of recurrence of 4.5 (HR 95% CI = 1.11-14.57; Cox Regression p = 0.034). These results show that Brazilian OpSCC patients exhibit a similar clinical and genetic profile in comparison to other populations. Molecular characterization is a promising tool for the definition of clinical subgroups, aiding in a more precise tailoring of treatment and prognostication.