Tumor-Intrinsic Perinuclear LOXL2: Prognostic Relevance and Relationship with YAP1 Activation Status in Oral Squamous Cell Carcinoma.

INTRODUCTION: Lysyl oxidase-like 2 (LOXL2) expression and function is frequently altered in different cancers but scarcely explored in oral squamous cell carcinoma (OSCC). This prompted us to investigate the clinical relevance of LOXL2 expression pattern in OSCC and also a possible crosstalk with Hippo/YAP1 pathway signaling. METHODS: Immunohistochemical analysis of LOXL2 protein expression was performed in 158 OSCC patient samples, together with Yes-associated protein 1 (YAP1) activation status. Correlations with clinicopathological parameters and patient survival were assessed. RESULTS: Tumor cell-intrinsic LOXL2 expression showed two distinct expression patterns: diffuse cytoplasmic staining (64.6%) and heterogeneous perinuclear staining (35.4%). Remarkably, perinuclear LOXL2 staining was significantly associated with lymph node metastasis, advanced clinical stage and perineural invasion. Moreover, patients harboring tumors with perinuclear LOXL2 expression exhibited significantly poorer disease-specific survival (DSS) rates, and perinuclear LOXL2 positivity gradually increased in relation to YAP1 activation. Patients harboring tumors with concomitant perinuclear LOXL2 and fully active YAP1 exhibited the worst DSS. Multivariate Cox analysis further revealed combined perinuclear LOXL2 and fully active YAP1 as a significant independent predictor of poor DSS. CONCLUSION: Tumor-intrinsic perinuclear LOXL2 emerges as a clinically and biologically relevant feature associated with advanced disease, tumor aggressiveness, and poor prognosis in OSCC. Moreover, this study unprecedentedly uncovers a functional relationship between perinuclear LOXL2 and YAP1 activation with major prognostic implications. Notably, combined perinuclear LOXL2 and fully active YAP1 was revealed as independent predictor of poor prognosis. These findings encourage targeting oncogenic LOXL2 functions for personalized treatment regimens.

Prognostic Significance of ß-Catenin in Relation to the Tumor Immune Microenvironment in Oral Cancer.

The aim of this study was to investigate the prognostic relevance of ß-catenin expression in oral squamous cell carcinoma (OSCC) and to explore relationships with the tumor immune microenvironment. Expression of ß-catenin and PD-L1, as well as lymphocyte and macrophage densities, were evaluated by immunohistochemistry in 125 OSCC patient specimens. Membranous ß-catenin expression was detected in 102 (81.6%) and nuclear ß-catenin in 2 (1.6%) tumors. There was an association between ß-catenin expression, tumoral, and stromal CD8+ T-cell infiltration (TIL) and also the type of tumor immune microenvironment (TIME). Tumors harboring nuclear ß-catenin were associated with a type II TIME (i.e., immune ignorance defined by a negative PD-L1 expression and low CD8+ TIL density), whereas tumors with membranous ß-catenin expression were predominantly type IV (i.e., immune tolerance defined by negative PD-L1 and high CD8+ TIL density). Combined, but not individual, high stromal CD8+ TILs and membranous ß-catenin expression was independently associated with better disease-specific survival (HR = 0.48, p = 0.019). Taken together, a combination of high stromal CD8+ T-cell infiltration and membranous ß-catenin in the tumor emerges as an independent predictor of better survival in OSCC patients.

Emerging Role of Decoy Receptor-2 as a Cancer Risk Predictor in Oral Potentially Malignant Disorders.

The aim of this study was to evaluate the expression of the senescence markers, Decoy Receptor 2 (DcR2) and Differentiated Embryo-Chondrocyte expressed gen 1 (DEC1), in oral potentially malignant disorders (OPMDs) to ascertain their possible association with oral cancer risk. The immunohistochemical analysis of DcR2 and DEC1 expression (along with p16 and Ki67 expression) was carried out in 60 patients with clinically diagnosed oral leukoplakia. Fifteen cases (25%) subsequently developed an invasive carcinoma. Correlations between protein marker expression, histological grade and oral cancer risk were assessed. DcR2, DEC1 and Ki67 protein expressions were found to correlate significantly with increased oral cancer risk, and also with an increased grade of dysplasia. Multivariate analysis demonstrated that DcR2 and Ki67 expression are independent predictors of oral cancer development. Our results evidence for the first time the potential of DcR2 as an early biomarker to assess oral cancer risk in patients with oral leukoplakia (HR = 59.7, p = 0.015), showing a superior predictive value to histology (HR = 4.225, p = 0.08). These findings reveal that the increased expression of DcR2 and DEC1 occurred frequently in OPMDs. In addition, DcR2 expression emerges as a powerful biomarker for oral cancer risk assessment in patients with oral leukoplakia.

The epidemiology and management of odontomas: a European multicenter study.

INTRODUCTION: Odontoma is the most commonly diagnosed odontogenic tumor of the oral cavity. The objective of the present study was to assess the demographic variables, patterns, diagnostic features, and management issues of odontomas treated at several European departments of maxillofacial and oral surgery. MATERIALS AND METHODS: This study was conducted at 8 European departments of oral surgery between January 1, 2004, and December 31, 2018. Only patients with odontomas were included. The following data were recorded for each patient: gender, age, comorbidities, site, size of odontomas, radiographic features, type of odontoma, treatment of odontomas, treatment of associated teeth, complications, and recurrence. RESULTS: A total of 127 patients (70 male and 57 female patients) with odontomas were included. The mean age was 22 years; 71 odontomas were found in the mandible, whereas 56 in the maxilla. In the mandible, the most frequently involved subsite was the parasymphysis, while in the maxilla, the most common subsite was the upper incisor region. The mean size of included odontomas was 15.3 mm. On the whole, 62 complex odontomas, 50 compound odontomas, and 15 mixed-type odontomas were observed. Complete excision of the odontomas was performed in 121 patients. In 24 patients, the extraction of deciduous teeth was performed, and in 43 patients, one or more permanent teeth were removed. Finally, in 9 patients, a partial excision of the odontoma was performed. Recurrence was observed in 4 cases out of 127 patients. CONCLUSIONS: Dental practitioners should be aware of the distinct clinical and radiographic features of odontoma in order to perform an appropriate and early diagnosis. Conventional radiography, such as panoramic radiograph, is often sufficient technique for a diagnosis after clinical suspicion or for an incidental diagnosis to prevent later complications, such as impaction or failure of eruption of teeth.

Quality of life following maxillofacial trauma in the elderly: a multicenter, prospective study.

BACKGROUND/AIMS: When facial trauma involves elderly patients, the possible presence of frailty and comorbidities in victims of trauma may worsen the posttraumatic symptoms and decrease quality of life. The aim of this multicenter study was to assess the quality of life following surgical or non-operative management of maxillofacial trauma in elderly patients. MATERIALS AND METHODS: This cohort study was based on the administration of validated self-administered questionnaires to all the geriatric patients (70 years or more) with facial fractures from the involved maxillofacial surgical units across Europe, since 1st January 2019 to 31st June 2019. The following questionnaires were administered: SF36 questionnaire; the VFQ-25 questionnaire; the Oral Health Impact Profile - 14 (OHIP14). Outcome variables were VFQ-25 and OHIP-14 results. RESULTS: A total of 37 patients (14 male and 23 female patients) met the inclusion criteria and were included in the study. Elderly patients had an improvement in almost all the categories examined by the SF-36 questionnaire 6 months after trauma, with the only exception of a worsening as for role limitations due to physical health. An improvement was observed in almost all the categories at SF-36 test. A worsening of scores of OHIP-14 for all the considered dimensions in the whole study population was observed too. CONCLUSIONS: Elderly patients following facial trauma experience significant emotional, social, and functional disturbances. We observed that emotional problems, energy/fatigue, social functioning, and generally social limitations played a great role in the decrease of QoL in elderly patients following maxillofacial trauma.

The epidemiology and management of odontogenic keratocysts (OKCs): A European multicenter study.

The objective of the present study was to assess the epidemiology including demographic variables, diagnostic features, and the management of odontogenic keratocyst (OKCs) at several European departments of maxillofacial and oral surgery. This study is based on a systematic computer-assisted database that allowed the recording of data from treated OKCs. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, site, size, radiographic features, treatment of OKCs, length of hospital stay, complications, recurrence, management and complications of eventual recurrence. A total of 405 patients, 249 male and 156 female, with 415 OKCs (407 sporadic and 8 syndromic lesions) were included in the study: 320 lesions were found in the mandible, whereas 95 were found in the maxilla. In the mandible, the most frequently involved subsite was the angle, whereas in the maxilla it was the molar region. The most frequently performed treatment option was enucleation plus curettage/peripheral ostectomy in 204 OKCs (recurrence rate, 9%). Decompression without residual cystectomy (recurrence rate, 66%), marsupialization with residual enucleation with the use of Carnoy's solution (recurrence rate, 50%), decompression with residual cystectomy (recurrence rate, 43%), and simple enucleation (recurrence rate, 24%) were the treatment options with the highest recurrence rates. An appropriate management of odontogenic keratocysts should be individualized, taking into consideration clinical and radiological findings, as well as patients' age and comorbidities.

The epidemiology and management of ameloblastomas: A European multicenter study.

The present study aimed at assessing the epidemiology including demographic variables, diagnostic features, and management of ameloblastomas at several European departments of maxillofacial and oral surgery. The following data were recorded for each patient: gender, age, voluptuary habits, comorbidities, site, size, radiographic features, type, histopathological features, kind of treatment, length of hospital stay, complications, recurrence, management and complications of the recurrence. A total of 244 patients, 134 males and 110 females with ameloblastomas were included in the study. Mean age was 47.4 years. In all, 81% of lesions were found in the mandible, whereas 19% were found in the maxilla. Mean size of included ameloblastomas was 38.9 mm. The most frequently performed treatment option was enucleation plus curettage/peripheral ostectomy in 94 ameloblastomas, followed by segmental resection (60 patients), simple enucleation (46 patients), and marginal resection (40 patients). A recurrence (with a mean follow up of 5 years) was observed in 47 cases out of 244 ameloblastomas (19.3%). Segmental resection was associated with a low risk of recurrence (p = 0003), whereas enucleation plus curettage/peripheral ostectomy was associated with a high risk of recurrence (p = 0002). A multilocular radiographic appearance was associated with a high risk of recurrence (p < .05), as well as the benign solid/multicystic histologic type (p < .05). Within the limitations of the study it seems that the management of ameloblastomas will probably remain controversial even in the future. Balancing low surgical morbidity with a low recurrence rate is a difficult aim to reach.

Prognostic Relevance of CD4+, CD8+ and FOXP3+ TILs in Oral Squamous Cell Carcinoma and Correlations with PD-L1 and Cancer Stem Cell Markers.

This study investigates the relevance of tumor-infiltrating lymphocytes (TILs) in oral squamous cell carcinoma (OSCC). Immunohistochemical analysis of stromal/tumoral CD4+, CD8+ and FOXP3+ TILs is performed in 125 OSCC patients. Potential relationships with the expression of tumoral PD-L1 and cancer stem cell (CSC) markers (NANOG, SOX2, OCT4, Nestin and Podoplanin (PDPN)) are assessed. CD4+ and CD8+ TILs are significantly associated with smoking and alcohol habits. CD4+ and CD8+ TILs show an inverse relationship with NANOG and SOX2 expression, and FOXP3+ TILs is significantly correlated with Nestin and PDPN expression. High infiltration of CD4+ and CD8+ TILs and a high tumoral CD8+/FOXP3+ ratio are significantly associated with tumors harboring positive PD-L1 expression. Infiltration of stromal/tumoral FOXP3+ TILs and a low stromal CD8+/FOXP3+ ratio are significantly associated with better disease-specific survival. Multivariate analysis reveals that the stromal CD8+/FOXP3+ TILs ratio is a significant independent prognostic factor. Regarding OSCC patient survival, the CD8+/FOXP3+ TILs ratio is an independent prognostic factor. TILs may act as biomarkers and potential therapeutic targets for OSCC.

Functional results of swallowing and aspiration after oral cancer treatment and microvascular free flap reconstruction: A retrospective observational assessment.

This study aimed to assess the functional swallowing outcomes in cohort of oral cancer patients treated with tumor resection and reconstruction by means of microvascular free flaps. Duration from onset to the last examination was classified into three periods: less than 12 months, from 13 to 24 months, and more than 24 months. Type of feeding, dysphagia, and laryngeal aspiration were the dependent variables, and the study was mainly focused on the data from the multivariate analysis. Fifty-one patients were included in the study. Twenty-one patients had dysphagia, 11 showed stasis in vallecula and pyriform sinuses, 9 experienced laryngeal penetration, and 8 aspirations. Surgery combined with radiochemotherapy was associated with a higher prevalence of dysphagia (p = 0.03). Frequency of dysphagia was higher in the first year after treatment and less frequent after 24 months (p = 0.003). Dysphagia was associated with laryngeal penetration (p = 0.001), and this with aspiration (p < 0.0005). In conclusion, as it seems that the method of reconstruction has a major influence on swallowing, when there are relevant alternatives in the way the reconstruction is done, always the approach should be chosen that reduces dysphagia to a minimum.

Genes involved in the epithelial-mesenchymal transition in oral cancer: A systematic review.

OBJECTIVE: Epithelial-mesenchymal transition (EMT) is considered the initial step in the invasion-metastasis cascade. The aim of this systematic review was to study the signature of genes involved in the EMT process in oral cancer (OC) confirmed by protein expression and its possible relationship with oral squamous cell carcinoma (OSCC) prognostic variables. MATERIALS AND METHODS: A search of the scientific literature was carried out with no start date restriction until 17 September 2020 in the electronic databases Pubmed/MEDLINE, Web of Science, Cochrane Library and Scopus, following specific eligibility criteria. The methodological quality of the included studies was assessed using the Newcastle-Ottawa tool. RESULTS: A total of 8 retrospective cohort studies were included, all of them performed in China and with low risk of bias. Overexpression of the genes HNRNPC, ITGA5, HMGA2 and SRSF3, and low expression of ALDH3A1 and ARID2 promote EMT in OC. The more advanced clinical stages of the TNM classification were significantly associated with overexpression of HNRNPC, ITGA5, HMGA2 and SRSF3, and low expression of ARID2. CONCLUSIONS: HNRNPC, ITGA5, HMGA2, SRSF3, ALDH3A1 and ARID2 genes were associated with EMT process. Over- or under-expression of these genes is associated with worse stages of OSCC and/or worse prognosis of the tumor. Further studies on this topic are needed in different countries to be able to confirm these results, since the detection of these genes can help to know which tumors have a worse prognosis.

Tumor-Infiltrating CD20+ B Lymphocytes: Significance and Prognostic Implications in Oral Cancer Microenvironment.

Immunohistochemical analysis of stromal/tumoral CD20+ B lymphocytes was performed in 125 OSCC patients. Correlations with immune profiles CD4+, CD8+, and FOXP3+ tumor-infiltrating lymphocytes (TILs), tumoral PD-L1, and stem-related factors NANOG and SOX2 were assessed, and also associations with clinical data and patient survival. There was a strong positive correlation between the infiltration of CD20+ B lymphocytes and other immune profiles (i.e., CD4+, CD8+, and FOXP3+ TILs, and CD68+ and CD163+ macrophages) both in stroma and tumor nests. Strikingly, CD20+ TILs were inversely correlated with NANOG/SOX2 expression. Stromal CD20+ TILs were significantly associated with T classification and second primary tumors. A stratified survival analysis showed that tumoral CD20+ TILs were significantly associated with prognosis in male and younger patients, with tobacco or alcohol consumption, high tumoral CD8+ TILs, low tumoral infiltration by CD68+ macrophages, positive PD-L1 expression, and negative NANOG/SOX2. Multivariate Cox analysis further revealed clinical stage and tumoral CD20+ TILs independently associated with disease-specific survival (HR = 2.42, p = 0.003; and HR = 0.57, p = 0.04, respectively). In conclusion, high CD20+ TIL density emerges as an independent good prognostic factor in OSCC, suggesting a role in antitumor immunity. This study also uncovered an inverse correlation between CD20+ TILs and CSC marker expression.

Management of maxillofacial trauma in the elderly: A European multicenter study.

BACKGROUND/AIMS: Management of maxillofacial trauma in the geriatric population poses a great challenge due to anatomical variations and medical comorbidities. The aim of this study was to analyze the management variables, timing, and outcomes of facial fractures in elderly patients (aged 70 years or more) at several European departments of oral and maxillofacial surgery. MATERIALS AND METHODS: This study was based on a systematic computer-assisted database that allowed the recording of data from all geriatric patients with facial fractures from the involved maxillofacial surgical units across Europe between 2013 and 2017. RESULTS: A total of 1334 patients were included in the study: 665 patients underwent closed or open surgical treatment. A significant association (P < .005) was found between the presence of concomitant injuries and a prolonged time between hospital admission and treatment. The absence of indications to treatment was associated with comorbidities and an older age (P < .000005). CONCLUSIONS: Elderly patients require specific attention and multidisciplinary collaboration in the diagnosis and sequencing of trauma treatment. A prudent attitude may be kept in selected cases, especially when severe comorbidities are associated and function is not impaired.

The epidemiology of edentulous atrophic mandibular fractures in Europe.

INTRODUCTION: The objective of the present study was to assess the demographic variables, causes, and patterns of edentulous atrophic fractures of the mandible managed at several European departments of oral and maxillofacial surgery. The results of this multicenter collaboration over a 10-year period are presented. METHODS: The data of all patients with fractures of the atrophic edentulous mandible from the involved maxillofacial surgical units across Europe between January 1, 2008, and December 31, 2017 were recorded: gender; age; voluptuary habits; comorbidities; etiology; fracture sites; synchronous body injuries; atrophy of the mandible according to Luhr classification; eventual type of treatment; timing of the eventual surgery; length of hospital stay. RESULTS: A total of 197 patients (86 male and 111 female patients) with 285 mandibular fractures were included in the study. Mean age of the study population was 75 years. Statistically significant associations were found between Luhr classes I - II and condylar fractures on one hand (p < .0005), and between Luhr class III and body and parasymphyseal fractures on the other hand (p < .05). Finally, 135 patients underwent open reduction and internal fixation, 56 patients did not undergo any intervention, and 6 patients underwent closed reduction. No statistically significant association was observed between treatment, timing of treatment, comorbidities, and concomitant injuries. CONCLUSIONS: The management of edentulous atrophic mandibular fractures remains challenging. Treatment decisions should continue to be based on the clinician's previous experience and on the degree of bone resorption in edentulous mandible in relation to fracture subsites.

Implant treatment in immunosuppressed renal transplant patients: A prospective case-controlled study.

OBJECTIVES: The aim of this clinical study was to evaluate long-term outcomes of implant therapy in a cohort of immunosuppressed renal transplant patients compared with a matched control group. MATERIAL AND METHODS: Pharmacologically immunosuppressed renal transplant patients received dental implant treatment between 2001 and 2011. Periodontal, clinical and radiographic parameters were prospectively measured with a mean follow-up of 116.8 months (range from 84 to 192 months). A matched controlled non-transplant sample receiving similar implant treatment in the same time was included as a control group. RESULTS: Implant survival rate was over 98% in both test and control groups (100% and 98.84%, respectively). Peri-implant mucositis was diagnosed in 46.80% of the implants in the study group and in 48.80% in the control group. Peri-implantitis occurred in 5.10% of the implants in the study group and in 8.10% of the controls. Wound healing and post-operative pain were similar in both groups. CONCLUSIONS: Despite the limitations of this study, pharmacological immunosuppression in renal transplant patients did not affect implant outcomes. Renal transplant patients should be carefully controlled periodically after implant treatment. CLINICAL IMPLICATIONS: The results from this investigation justify the use of dental implants for the dentalrehabilitation of immunosuppressed patients after renal transplantation provided they follow the necessarylong-term monitoring and regular maintenance of their oral and systemic health.

Clinicopathologic and Surgical Study of Pleomorphic Adenoma of the Parotid Gland: Analysis of Risk Factors for Recurrence and Facial Nerve Dysfunction.

PURPOSE: To determine whether clinicopathologic or surgical features are risk factors for recurrence and facial nerve dysfunction in pleomorphic adenoma (PA) of the parotid gland. PATIENTS AND METHODS: The records of 198 patients surgically treated for a PA of the parotid gland from 1999 through 2013 were retrospectively reviewed to identify patients who developed a tumor recurrence. The Fisher exact test and Mann-Whitney U test were used to analyze patient characteristics between recurrent and non-recurrent PAs. Logistic regression was used to determine the risks of recurrence and facial nerve dysfunction. RESULTS: Twenty-three patients (11.6%) developed a recurrence. Patients with tumor recurrence were notably younger than patients without recurrence. Of the 14 patients who underwent enucleation, 11 (78.6%) developed residual disease, as did 10 of 165 patients (6%) managed by a superficial parotidectomy (P < .0005). Furthermore, the risk of residual disease was 9.3 to 21.6 times higher in patients who underwent enucleation than in those who underwent a total or superficial parotidectomy. For tumor histology, recurrence was observed in 3 (15.8%) of the 19 cellular types, 18 (11.5%) of 157 classic cases, and 1 (4.8%) of 21 myxoid cases (P = .5). The risk of recurrence with positive resection margins was 49 times higher than with negative margins (P = .001). CONCLUSION: Young age, enucleation, and positive margins are risk factors for residual pleomorphic adenoma, and surgical technique and histomorphologic features are associated with increased facial nerve dysfunction.

Implant treatment in pharmacologically immunosuppressed liver transplant patients: A prospective-controlled study.

OBJECTIVES: The main objective of this prospective study was to evaluate the long-term outcome of implant therapy in liver transplant patients (LTP). The secondary goal was to assess several implant- and patient-dependent variables, such as peri-implantitis (PI), peri-implant mucositis (PIM), bone loss (BL), and immediate postoperative complications. MATERIAL AND METHODS: Two groups, including 16 pharmacologically immunosuppressed LTP and 16 matched controls, received 52 and 54 implants, respectively, between 1999 and 2008. After evaluating the postoperative healing, a mean follow-up of more than 8 years was carried out, and radiographic, clinical, and periodontal parameters were recorded to evaluate implant survival and implant- and patient-dependent outcomes. RESULTS: The early postsurgical complications were similar in both groups. Implant survival rate was 100% in the LTP group and 98.15% in the CG. PIM was diagnosed in 35.42% of the implants and 64.29% of the patients of LTP group (LTPG) and in 43.40% of the implants and 56.25% of the patients in the CG. PI was detected in 4.17% of the implants and 7.10% of the patients in the LTPG and in 9.43% of the implants and 18.80% of the patients in the CG. CONCLUSION: Pharmacologically immunosuppression in liver transplant patients was not a risk factor for implant failure, nor for the incidence of peri-implant diseases. Liver transplant is not a contraindication for dental implant treatment, although these patients should be carefully monitored during follow-up care.

Elemental and isotopic analysis of oral squamous cell carcinoma tissues using sector-field and multi-collector ICP-mass spectrometry.

Elemental and isotopic analysis via single-collector and multi-collector ICP-mass spectrometry, respectively, have been explored as a tool for identifying potential differences between non-tumor and oral squamous cell carcinoma tissues. Elemental concentrations of major and minor elements, known to be essential for different processes in the cell (i.e. Na, Ca, Mg, K, P, Fe, Cu and Zn), have been determined and results for cancerous and non-cancerous tissues collected from the same individual have been compared. Among the elements studied, only Mg, K and P turned out to be significantly higher in concentration in the tumor tissues. However, a shift towards higher and wider concentration ranges has also been observed for Cu and Zn in the tumor samples, whereas for Ca lower concentrations were established. Possible isotope ratio variations for Cu and Zn in both biological tissues have also been evaluated with the same goal. δ66Zn results did not provide an obvious trend, but in the case of Cu, a clear distinction between the tumor and non-tumor tissues was observed: δ65Cu values ranged between -0.68% and 0.03% in the non-tumor tissues, whereas tumor samples turned out to be enriched in 65Cu, with δ65Cu values between 0.10% and 0.93%. These results confirm the considerable potential of isotopic and elemental studies for biomedical purposes.

Prevalence of human papillomavirus in oral squamous cell carcinomas in northern Spain.

The aim of this study was to analyze the prevalence of high-risk HPV in oral squamous cell carcinoma (OSCC) in a northern Spanish population, as well as to ascertain the prognostic role of p16INK4a expression. The examination samples were collected from paraffin tissue blocks, from 125 patients surgically treated between 1996 and 2007. All cases were histologically evaluated, and the presence of HPV was assessed by p16 and p53immunohistochemistry followed by DNA detection by in situ hybridization (ISH) and polymerase chain reaction (PCR) amplification using the combination of consensus primers MY11/GP6 + . Fourteen cases (11 %) were p16-immunopositive, and p53 was scored positive in 73 cases (58 %). Five cases (4 %) showed a simultaneous p16-positive and p53-negative immunostaining. ISH was negative in all the cases. Among the p16INK4a-immunopositive cases, PCR amplification failed to reveal HPV DNA in any tumor samples. There were no statistically significant differences in any clinical or pathological characteristics of the patients regarding p16INK4a expression. T classification, neck-node metastasis, and clinical stage showed outcome relevance. However, no significant differences in cause-specific survival based on p16INK4a were observed. We did not find any high-risk HPV types in our patients, thus, are unlikely that HPV has an important role in the etiology of OSCC. p16INK4a protein was neither an accurate marker of HPV infection nor a prognosis marker in OSCC.