Standardised definitions and diagnostic criteria for extranodal extension detected on histopathological examination in head and neck cancer: Head and Neck Cancer International Group consensus recommendations.

Detection of extranodal extension on histopathology in surgically treated head and neck squamous cell carcinoma indicates poor prognosis. However, there is no consensus on the diagnostic criteria, interpretation, and reporting of histology detected extranodal extension, which has contributed to conflicting evidence in the literature, and likely clinical inconsistency. The Head and Neck Cancer International Group conducted a three-round modified Delphi process with a group of 19 international pathology experts representing 15 national clinical research groups to generate consensus recommendations for histology detected extranodal extension diagnostic criteria. The expert panel strongly agreed on terminology and diagnostic features for histology detected extranodal extension and soft tissue metastasis. Moreover, the panel reached consensus on reporting of histology detected extranodal extension and on nodal sampling. These consensus recommendations, endorsed by 19 organisations representing 34 countries, are a crucial development towards standardised diagnosis and reporting of histology detected extranodal extension, and more accurate data collection and analysis.

Diagnostic Challenges during Inflammation and Cancer: Current Biomarkers and Future Perspectives in Navigating through the Minefield of Reactive versus Dysplastic and Cancerous Lesions in the Digestive System.

In the setting of pronounced inflammation, changes in the epithelium may overlap with neoplasia, often rendering it impossible to establish a diagnosis with certainty in daily clinical practice. Here, we discuss the underlying molecular mechanisms driving tissue response during persistent inflammatory signaling along with the potential association with cancer in the gastrointestinal tract, pancreas, extrahepatic bile ducts, and liver. We highlight the histopathological challenges encountered in the diagnosis of chronic inflammation in routine practice and pinpoint tissue-based biomarkers that could complement morphology to differentiate reactive from dysplastic or cancerous lesions. We refer to the advantages and limitations of existing biomarkers employing immunohistochemistry and point to promising new markers, including the generation of novel antibodies targeting mutant proteins, miRNAs, and array assays. Advancements in experimental models, including mouse and 3D models, have improved our understanding of tissue response. The integration of digital pathology along with artificial intelligence may also complement routine visual inspections. Navigating through tissue responses in various chronic inflammatory contexts will help us develop novel and reliable biomarkers that will improve diagnostic decisions and ultimately patient treatment.

Human Papillomavirus 16 DNA Methylation Patterns and Investigation of Integration Status in Head and Neck Cancer Cases.

Persistent high-risk human papillomavirus (HPV) infection is a pivotal factor in the progression of cervical cancer. In recent years, an increasing interest has emerged in comprehending the influence of HPV on head and neck squamous cell carcinoma (HNSCC). Notably, it is well established that HPV-associated HNSCC show cases with distinct molecular and clinical attributes compared to HPV-negative cases. The present study delves into the epigenetic landscape of HPV16, specifically its L1 gene and untranslated region (UTR), through pyrosequencing, while the HPV16 DNA physical status was evaluated using E2/E6 ratio analysis in HPV16-positive HNSCC FFPE biopsies. Our findings reveal substantial methylation across six sites within the HPV16 L1 gene and seven sites in the UTR. Specifically, methylation percentages of two L1 CpG sites (7136, 7145) exhibit significant associations with tumor histological grade (p < 0.01), while proving concurrent methylation across multiple sites. The HPV16 DNA physical status was not correlated with the methylation of viral genome or tumor characteristics. This is the first study that examines epigenetic modifications and the HPV16 DNA physical status in Greek HNSCC patients. Our findings suggest an orchestrated epigenetic modulation among specific sites, impacting viral gene expression and intricate virus-host interactions.

Experimental Candida albicans osteomyelitis: Microbiologic, antigenic, histologic, and 18FDG-PET-CT imaging characteristics in a newly established rabbit model.

Candida osteomyelitis is a debilitating disease that is difficult to diagnose and treat. As there are no animal models or prospective studies for this uncommon infection, little is known about the pathogenesis, diagnosis, or treatment. We therefore sought to establish an animal model for the study of the pathophysiology, diagnostic modalities, and therapeutic interventions of Candida osteomyelitis. We developed a modified version of the Norden rabbit model of tibial osteomyelitis, in which the right tibia was inoculated intraoperatively with different inocula of C. albicans or normal saline as control. On days 7, 14, and 21 after inoculation, the animals underwent bone radiography, 18-fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography (PET/CT) scan, and blood sampling for blood cultures, blood counts, erythrocyte sedimentation rate, and Candida mannan antigen serum levels. On day 21, animals were euthanized, and infected tibias harvested for culture and histology. Among eight evaluable animals inoculated with 1 × 106 to 1 × 107 cfu, histology and bone cultures established the presence of Candida osteomyelitis in seven, with a host response of neutrophils, mononuclear cells, multinucleate giant cells, fibrosis, and necrosis. Infected animals demonstrated radiological signs of osteomyelitis with significantly increased tracer uptake in 18FDG-PET/CT scans (P < .01) and elevated serum mannan levels (P < .01). All blood cultures were negative. Indices of inflammation were only slightly increased. In conclusion, we report successful establishment of a new animal model of Candida albicans osteomyelitis that may be applicable to advancing our understanding of the pathophysiology, diagnostic modalities, and treatment of this debilitating infection.

Lower adenoma miss rate with FUSE vs. conventional colonoscopy with proximal retroflexion: a randomized back-to-back trial.

Background and study aims Full-spectrum colonoscopy (FSC) promises to increase adenoma detection by providing a wider field of view. The aim of this study was to compare adenoma miss rates of FSC with those of conventional colonoscopy complemented by right-colon re-examination using scope retroflexion (CC/R). Patients and methods At two tertiary endoscopy facilities, patients who were scheduled for colonoscopy for the assessment of symptoms or for colorectal cancer screening/surveillance were randomized (1:1) to undergo same-day, back-to-back colonoscopies (FSC or CC/R first), performed by one of five endoscopists who had documented adenoma detection rates > 35 %. Per-protocol data were analyzed. Results We randomized 220 patients. There were five FSC technical failures (three air pump and two left screen); therefore, 107 and 108 cases were analyzed in the FSC and CC/R index procedure arms, respectively. Withdrawal times were similar for FSC and CC/R (7.7 minutes vs. 7.6 minutes). Overall, we detected 3 cancers and 153 adenomas (FSC = 92; CC/R = 61); 81 were detected in the proximal colon, 3 of which were detected by retroflexed examination. By per-lesion analysis, FSC showed a significantly lower adenoma miss rate compared with CC/R overall (10.9 % [95 % confidence interval (CI) 3.8 to 18.1] vs. 33.7 % [95 %CI 23.4 to 44.1]) and in the proximal colon (13.9 % [95 %CI 2.6 to 25.2] vs. 42.2 % [95 %CI 27.8 to 56.7]). The advanced adenoma miss rate was lower with FSC overall (4.3 % [95 %CI - 4.0 to 12.7] vs. 25.9 % [95 %CI 9.4 to 42.5]). There were no adverse events. Conclusions FSC outperformed conventional colonoscopy with right-colon scope retroflexion in the detection of missed adenomas, both overall and in the proximal colon, even when performed by experienced endoscopists.Trial registered at ClinicalTrials.gov (NCT02117674).

'Prostate Abscess' as the Initial Manifestation of Granulomatosis with Polyangiitis (Wegener's Granulomatosis).

Prostatic involvement in granulomatosis with polyangiitis (GWP), formerly known as Wegener's granulomatosis, is rare, mostly arising in the context of systemic involvement. Prostatic involvement as the first manifestation of this systemic disease is exceptionally rare. We hereby present the case of a 41-year-old male patient who underwent transurethral prostate resection for what was initially diagnosed as suppurative, focally necrotizing prostatitis. Prolonged postoperative fever that did not respond to various treatments, as well as the subsequent appearance of a left pleural effusion, a left upper pulmonary lobe lesion and cutaneous nodules, led to a reevaluation of histological slides which, along with the determination of serum c-ANCA/anti-PR3 antibody levels, established the diagnosis of GWP. Physicians, and especially urologists and infectious diseases specialists, should be aware of this rare association and consider GWP in the event of nonresolving prostatitis, especially when characteristic symptoms from other systems appear.

An unusual case of diffuse Merkel cell carcinoma successfully treated with low dose radiotherapy.

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine carcinoma of the skin. MCC should be included in the diagnosis of a rapidly growing infiltrating mass and histology as well as laboratory investigations such as Merkel cell polyoma virus (MCPyV) detection are valuable in its diagnosis. We present an unusual case of giant MCC-positive MCPyV in a Greek woman located on the lower leg. Our patient is very unusual in terms of her extensive MCC and her rapid and complete response to radiotherapy.

Seasonal Variation in Sudden Cardiac Death: Insights from a Large United Kingdom Registry.

BACKGROUND: Sudden cardiac death (SCD) is relatively common and may occur in apparently healthy individuals. The role of seasonal variation as a risk factor for SCD is poorly understood. The aim of this study was to investigate whether SCD exhibits a predilection for specific seasons. METHODS: We reviewed a database of 4751 cases of SCD (mean age 38 ± 17 years) referred to our Center for Cardiac Pathology at St George's University of London between 2000 and 2018. Clinical information was obtained from referring coroners who were asked to complete a detailed questionnaire. All cases underwent macroscopic and histological evaluation of the heart, by expert cardiac pathologists. RESULTS: SCD was more common during winter (26%) and rarer during summer (24%), p = 0.161. Significant seasonal variation was not observed among cases of sudden arrhythmic death syndrome (SADS, 2910 cases) in which the heart is structurally normal. In contrast, a significant difference in seasonal distribution among decedents exhibiting cardiac structural abnormalities at the post-mortem examination (n = 1841) was observed. In this subgroup, SCDs occurred more frequently during winter (27 %) compared to summer (22%) (p = 0.007). In cases diagnosed with a myocardial disease (n = 1399), SCD was most common during the winter (27%) and least common during the summer (22%) (p = 0.027). CONCLUSIONS: While SADS occurs throughout the year with no seasonal variation, SCD due to structural heart disease appears to be more common during the winter. Bio-meteorological factors may be potential triggers of SCD in individuals with an underlying structural cardiac abnormality.

Malignant Brenner Tumor of the Ovary: A Systematic Review of the Literature.

BACKGROUND: Malignant Brenner tumors are rare ovarian tumors, accounting for less than 1% of malignant ovarian neoplasms. The aim of this manuscript is to systematically review the current literature concerning malignant Brenner tumors. METHODS: We searched three medical databases (PubMed, Scopus, and Web of Science) for relevant articles published until 15 September 2023. RESULTS: After applying inclusion and exclusion criteria, 48 manuscripts describing 115 cases were included in this study from the English literature. CONCLUSIONS: We analyzed the demographic, clinical, pathological, and oncological characteristics of 115 patients with malignant Brenner tumors. The statistical analysis showed that recurrence was marginally statistically significantly related to tumor stage and was more common in patients with ascites and in women with abnormal CA-125 levels; patients that were treated with lymphadenectomy had better disease-specific survival.

Evidence That Cigarette Smoking Alters Alveolar Type I Cell Nuclear Fractal Dimension.

A large number of alveolar type I and II cells from the lungs of both smokers and non-smokers was collected using 40x magnification histological images from our digital archive. These images underwent a transformation into binary images of nuclear contours, followed by the application of the box-counting method. Statistical analysis revealed a significant difference in the mean box-counting dimension values between type I cells of smokers and non-smokers. However, no significant difference was observed in the mean fractal dimensions of alveolar type II cells. This study provides preliminary evidence of the impact of cigarette smoking on the nuclear shape of alveolar type I cells. Given the high toxicity of cigarette smoke to lung cells and the interconnection between morphology and function, further study is needed to understand its impact on the nuclear shape of these cells. Future research should also explore the effects of second-hand smoke on cell shape.

Uterine collision tumor (PEComa and endometrioid carcinoma) in a tuberous sclerosis patient: a case report.

Perivascular epithelioid cell tumors are very rare mesenchymal neoplasms arising in various locations, such as the female genital tract, kidney, lung, prostate, bladder, pancreas, soft tissues, and bone. They possess a unique immunophenotype, co-expressing myogenic and melanocytic markers; molecular findings include mutations of tuberous sclerosis complex and translocations of transcription factor E3, a member of the microphthalmia transcription factor gene family. We herewith report a uterine collision tumor consisting of a perivascular epithelioid cell tumor and a moderately differentiated endometrial endometrioid carcinoma in a patient with genetically proven tuberous sclerosis; two leiomyomas were also found in contact with the tumor. Although two such cases one with a benign and another with a malignant perivascular epithelioid cell tumor have previously been reported, ours is, to our knowledge, the first reported in a tuberous sclerosis patient.

Expression profile of miRNAs computationally predicted to target PDL-1 in cervical tissues of different histology groups.

Background: Human papilloma virus (HPV) is considered a successful pathogen as it has the ability to evade host immune responses and establish long-term persistent infection. It has been reported that programmed death ligand 1 (PDL-1) expression is correlated with HPV-positivity and is increased with lesion progression or tumor metastasis in cervical cancer. The expression of microRNAs (miRNAs) is often deregulated in cancer, and their potential targets are affected. Methods: RNA was extracted from formalin-fixed paraffin-embedded (FFPE) cervical samples of different histological types, previously typed for the presence of HPV. A specific quantitative polymerase chain reaction (qPCR) protocol with SYBR Green was used to check for the expression of four miRNAs that were computationally predicted to target PDL-1. Results and conclusion: hsa-miR-20a-5p and hsa-miR-106b-5p showed an expression increase with the severity of the lesions, while hsa-miR-125b-5p depicted a significant decrease in its expression in cancerous samples when compared to normal samples.

Multiple cerebral microinfarcts: an uncommon presentation of Cerebral Amyloid Angiopathy-related inflammation.

BACKGROUND: Cerebral Amyloid Angiopathy-related inflammation (CAA-ri) is a distinct but rare subset of CAA. The greater availability of high resolution Magnetic Resonance Imaging (MRI) has currently allowed the increasing recognition and diagnosis of this entity, without the risk of a brain biopsy. However, in rare cases with typical clinical characteristics but uncommon neuroimaging findings at presentation, the brain-biopsy is required for an early and reliable diagnosis. CASE DESCRIPTION: A 71-year-old man with arterial hypertension presented due to 1-week history of headache, vomiting, disorientation and impaired consciousness. Brain MRI revealed multiple acute cortical/subcortical microinfarcts, scarce microbleeds, extensive right parietooccipital and left frontotemporal leptomeningeal enhancement. After an extensive diagnostic work-up, excluding infectious, neoplastic and autoimmune etiologies, the patient underwent brain-biopsy. Histology disclosed amyloid deposition in an arteriolar wall and the patient fulfilled diagnostic criteria for probable CAA-ri with supporting pathology. He received intravenous methylprednisolone, followed by oral tapering with steroids showing clinical and radiological improvement with complete resolution of gadolinium enhancement. Follow-up MRI revealed an increase of cerebral microbleeds and the patient fulfilled CAA-ri neuroimaging criteria. CONCLUSIONS: This case highlights the importance of continuous vigilance from clinical neurologists to detect CAA-ri diagnosis and the diagnostic value of brain-biopsy in CAA-ri patients with atypical neuroimaging presentation, such as acute microinfarcts. The early diagnosis and the prompt treatment initiation can improve the prognosis and the evolution of this rare disorder.

Prevalence of Small Intestinal Bacterial Overgrowth Syndrome in Patients with Non-Alcoholic Fatty Liver Disease/Non-Alcoholic Steatohepatitis: A Cross-Sectional Study.

INTRODUCTION: Non-alcoholic fatty liver disease (NAFLD) is a multifactorial, wide-spectrum liver disorder. Small intestinal bacterial overgrowth (SIBO) is characterized by an increase in the number and/or type of colonic bacteria in the upper gastrointestinal tract. SIBO, through energy salvage and induction of inflammation, may be a pathophysiological factor for NAFLD development and progression. AIM/METHODS: Consecutive patients with histological, biochemical, or radiological diagnosis of any stage of NAFLD (non-alcoholic fatty liver [NAFL], non-alcoholic steatohepatitis [NASH], cirrhosis) underwent upper gastrointestinal endoscopy. Duodenal fluid (2cc) was aspirated from the 3rd-4th part of duodenum into sterile containers. SIBO was defined as ≥103 aerobic colony-forming units (CFU)/mL of duodenal aspirate and/or the presence of colonic-type bacteria. Patients without any liver disease undergoing gastroscopy due to gastroesophageal reflux disease (GERD) comprised the healthy control (HC) group. Concentrations (pg/mL) of tumor necrosis factor alpha (TNFα), interleukin (IL)-1ß, and IL-6 were also measured in the duodenal fluid. The primary endpoint was to evaluate the prevalence of SIBO in NAFLD patients, while the comparison of SIBO prevalence among NAFLD patients and healthy controls was a secondary endpoint. RESULTS: We enrolled 125 patients (51 NAFL, 27 NASH, 17 cirrhosis, and 30 HC) aged 54 ± 11.9 years and with a weight of 88.3 ± 19.6 kg (NAFLD vs. HC 90.7 ± 19.1 vs. 80.8 ± 19.6 kg, p = 0.02). Overall, SIBO was diagnosed in 23/125 (18.4%) patients, with Gram-negative bacteria being the predominant species (19/23; 82.6%). SIBO prevalence was higher in the NAFLD cohort compared to HC (22/95; 23.2% vs. 1/30; 3.3%, p = 0.014). Patients with NASH had higher SIBO prevalence (6/27; 22.2%) compared to NAFL individuals (8/51; 15.7%), but this difference did not reach statistical significance (p = 0.11). Patients with NASH-associated cirrhosis had a higher SIBO prevalence compared to patients with NAFL (8/17; 47.1% vs. 8/51; 15.7%, p = 0.02), while SIBO prevalence between patients with NASH-associated cirrhosis and NASH was not statistically different (8/17; 47.1% vs. 6/27; 22.2%, p = 0.11). Mean concentration of TNF-α, IL-1ß, and IL-6 did not differ among the different groups. CONCLUSION: The prevalence of SIBO is significantly higher in a cohort of patients with NAFLD compared to healthy controls. Moreover, SIBO is more prevalent in patients with NASH-associated cirrhosis compared to patients with NAFL.

Diffuse panniculitis in a teenage male with ZZ α1-antitrypsin deficiency.

Diffuse panniculitis is a rare manifestation of α1-ATD, albeit perhaps the most fulminant and life-threatening complication, associated usually with ZZ phenotype. Intravenous α1-AT treatment is lifesaving. https://bit.ly/3EDmCzT.

Cervical HPV Infections, Sexually Transmitted Bacterial Pathogens and Cytology Findings-A Molecular Epidemiology Study.

Prevalent cervical HPV infection and high-risk HPV persistence consequences have been extensively investigated in the literature; nevertheless, any causative interrelations of other sexually transmitted bacterial infections (STIs) with cervical HPV infection have not yet been fully elucidated. This study aimed to investigate the possible association of STIs with cervical cytology aberrations and HPV genotyping results in a representative sample of predominantly young Greek women. Liquid-based cytology and molecular detection for bacterial STIs and HPV as well as extended HPV genotyping were simultaneously assessed in cervical samples from 2256 individuals visiting several urban outpatient Gynecology Departments for well-woman visits or cervical screening throughout a 20-month period. All specimens were centrally processed with validated molecular assays. The mean age of the studied women was 37.0 ± 11.7 years; 722 women (33.30%) tested positive for STI (mean age 34.23 ± 10.87 years). A higher mean age (38.34 ± 11.83 years (p < 0.05)) was associated with negative STI testing. Chlamydia trachomatis was detected in 59 individuals (8.2%), Mycoplasma hominis in 156 (21.6%), Mycoplasma genitalium in 14 (1.9%), and Ureaplasma spp. in 555 (76.9%); infections with two bacterial pathogens were identified in 73 samples (10.1%). Cervical HPV was detected in 357 out of 1385 samples with a valid HPV typing result (25.8%). The mean age of HPV-positive women was 32.0 ± 8.4 years; individuals testing HPV-negative were slightly older (N = 1028): 34.4 ± 9.2 (p < 0.05). Among the 1371 individuals with valid results both for bacterial STIs and cervical HPV detection, women with an HPV-positive sample were more likely to harbor an STI (OR: 2.69, 95% CI 2.10-3.46, p < 0.05). Interestingly, bacterial STI positivity illustrated significant heterogeneity between NILM and LSIL cases, with 28.88% of NILM and 46.33% of LSIL cases harboring an STI, respectively (p < 0.05). In brief, in a population with a high prevalence for STIs, especially Ureaplasma spp., an association was documented between bacterial pathogen detection and cervical HPV infection, as well as abnormal cytology; these findings merit further investigation.

Primary Adrenal Lymphomas with Cushing's Syndrome: Two Cases with Evidence of Endogeneous Cortisol Production by the Neoplastic Lymphoid Cells.

Primary adrenal lymphoma (PAL) is a rare entity that presents as unilateral or bilateral rapidly growing adrenal masses, with signs and symptoms most commonly related to adrenal insufficiency due to the mass effect on the surrounding tissues. Although steroeidogenesis has not been previously described in PAL, we herein report two cases of PAL presenting as adrenal incidentalomas (AIs) that demonstrated autonomous cortisol production. A 52-year-old woman presented with lumbar pain; a computed tomography (CT) scan demonstrated a left AI measuring 8.5 × 15 × 10 cm. Similarly, an 80-year-old woman presented with lumbar pain, demonstrating in a CT scan a bilateral AI (right: 9 × 6.5 cm, left: 3.6 × 3.2 cm). Both cases underwent a full hormonal evaluation according to the algorithm for the investigation of AIs, demonstrating increased 24-h cortisol excretion, suppressed fasting adrenocorticotropic hormone (ACTH) levels, and non-suppressed serum cortisol levels in both the overnight and the low-dose dexamethasone suppression tests, indicating autonomous cortisol secretion and Cushing's syndrome. In a relatively short time, both patients developed night sweats, and their clinical picture deteriorated, while the CT scans showed increased dimensions of the masses with radiological characteristics compatible to lymphoma. Both patients underwent ultrasound-guided biopsies (FNBs), revealing infiltration of the left adrenal by diffuse large B-cell lymphoma in the first case, whereas bilateral adrenal infiltration from the same histological type was noted in the second case. Subsequently, they were treated with immunochemotherapy, but the second patient died from an infection shortly after the initiation of the treatment. To our knowledge, this is the first report of PAL presenting with Cushing's syndrome due to autonomous cortisol production, indicating that neoplastic lymphoid cells in PAL might acquire the potential for steroidogenesis; therefore, more cases of PAL should be analyzed so as to further elucidate the complex pathogenesis and the natural course of this entity.

Significance of MYB and NTRK Expression in Head and Neck Adenoid Cystic Carcinoma.

BACKGROUND/AIM: Adenoid cystic carcinoma (ACC) is an aggressive neoplasm even though it has low-grade histological appearance and slow growth. The aim of this study was to identify the immunohistochemical and molecular characteristics of ACC, as well as their correlation with the clinical course of patients. PATIENTS AND METHODS: This is a retrospective multicenter analysis. We included 50 patients diagnosed with ACC in the head and neck between 2000 and 2021. The expression of MYB proto-oncogene transcription factor (MYB), neurotrophic tyrosine kinase receptor (NTRK), human epidermal receptor-2 (HER-2), and Ki-67 was examined through immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). We also performed a clinical follow-up of the patients. RESULTS: The median age of the patients was 58.5 years; moreover, 54% of the patients were male. Compared with female patients, male patients were at a higher risk of both recurrence and death. No HER-2-positive cases were revealed. MYB expression was positive in 28 (56%) cases. However, MYB expression did not significantly affect survival. NTRK expression was positive in eight (16%) cases. NTRK-positive patients had worse overall survival (OS) than NTRK-negative patients (p=0.0246). Additionally, the percentage of NTRK-stained cells was negatively correlated with disease-free survival (p=0.0016) and OS (p=0.0027). CONCLUSION: There was no correlation between MYB positivity and survival. Contrarily, NTRK-positive patients had worse survival, indicating that NTRK is a negative prognostic factor. Tropomyosin receptor kinase inhibitors can be used to treat these patients. Furthermore, MYB-targeted inhibitors are promising therapeutic agents.

Next-generation sequencing (NGS) profiling of matched tumor and circulating tumor DNA (ctDNA) in head and neck squamous cell carcinoma (HNSCC).

OBJECTIVES: The aim of this pilot study was to evaluate the presence of somatic mutations in matched tumor and circulating DNA (ctDNA) samples from patients with primary head and neck squamous cell carcinoma (HNSCC) and assess the association of changes in ctDNA levels with survival. MATERIALS AND METHODS: Our study included 62 patients with stage I-IVB HNSCC treated with surgery or radical chemoradiotherapy with curative intent. Plasma samples were obtained at baseline, at the end of treatment (EOT), and at disease progression. Tumor DNA was extracted from plasma (ctDNA) and tumor tissue (tDNA). The Safe Sequencing System was used assess the presence of pathogenic variants in four genes (TP53, CDKN2A, HRAS and PI3KCA) in both ctDNA and tDNA. RESULTS: Forty-five patients had available tissue and plasma samples. Concordance of genotyping results between tDNA and ctDNA at baseline was 53.3%. TP53 mutations were most commonly identified at baseline in both ctDNA (32.6%) and tDNA (40%). The presence of mutations in this restricted set of 4 genes in tissue samples at baseline was associated with decreased overall survival (OS) [median 58.3 months for patients with mutations vs. 89 months for patients without mutations, p < 0.013]. Similarly, patients presenting with mutations in ctDNA had shorter OS [median 53.8 vs. 78.6 months, p < 0.037]. CtDNA clearance at EOT did not show any association with PFS or OS. CONCLUSIONS: Liquid biopsy enables real-time molecular characterization of HNSCC and might predict survival. Larger studies are needed to validate the utility of ctDNA as a biomarker in HNSCC.