Immune checkpoint inhibitors induce acute interstitial nephritis in mice with increased urinary MCP1 and PD-1 glomerular expression.

INTRODUCTION: Immune checkpoint inhibitors (ICIs) induce acute interstitial nephritis (AIN) in 2-5% of patients, with a clearly higher incidence when they are combined with platinum derivatives. Unfortunately, suitable disease models and non-invasive biomarkers are lacking. To fill this gap in our understanding, we investigated the renal effects of cisplatin and anti-PD-L1 antibodies in mice, assessing PD-1 renal expression and cytokine levels in mice with AIN, and then we compared these findings with those in AIN-diagnosed cancer patients. METHODS: Twenty C57BL6J mice received 200 µg of anti-PD-L1 antibody and 5 mg/kg cisplatin intraperitoneally and were compared with those receiving cisplatin (n = 6), anti-PD-L1 (n = 7), or saline (n = 6). After 7 days, the mice were euthanized. Serum and urinary concentrations of TNFα, CXCL10, IL-6, and MCP-1 were measured by Luminex. The kidney sections were stained to determine PD-1 tissue expression. Thirty-nine cancer patients with AKI were enrolled (AIN n = 33, acute tubular necrosis (ATN) n = 6), urine MCP-1 (uMCP-1) was measured, and kidney sections were stained to assess PD-1 expression. RESULTS: Cisplatin and anti PD-L1 treatment led to 40% AIN development (p = 0.03) in mice, accompanied by elevated serum creatinine and uMCP1. AIN-diagnosed cancer patients also had higher uMCP1 levels than ATN-diagnosed patients, confirming our previous findings. Mice with AIN exhibited interstitial PD-1 staining and stronger glomerular PD-1 expression, especially with combination treatment. Conversely, human AIN patients only showed interstitial PD-1 positivity. CONCLUSIONS: Only mice receiving cisplatin and anti-PDL1 concomitantly developed AIN, accompanied with a more severe kidney injury. AIN induced by this drug combination was linked to elevated uMCP1, consistently with human AIN, suggesting that uMCP1 can be potentially used as an AIN biomarker.

Recommendations for the use of biomarkers for head and neck cancer, including salivary gland tumours: A Consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology.

The treatment of head and neck and salivary gland tumours is complicated and is constantly evolving. Prognostic and predictive indicators of response to treatment are enormously valuable for designing individualized therapies, which justifies their research and validation. Some biomarkers, such as p16, Epstein-Barr virus, PD-L1, androgen receptors and HER-2, are already used routinely in clinical practice. These biomarkers, along with other markers that are currently under development, and the massively parallel sequencing of genes, ensure future advances in the treatment of these neoplasms. In this consensus, a group of experts in the diagnosis and treatment of tumours of the head and neck and salivary glands were selected by the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica - SEAP) and the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica - SEOM) to evaluate the currently available information and propose a series of recommendations to optimize the determination and daily clinical use of biomarkers.

Recommendations for the use of biomarkers for head and neck cancer, including salivary gland tumours: A Consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology / Recomendaciones para el uso de biomarcadores para cáncer de cabeza y cuello, incluyendo tumores de glándulas salivares: consenso de la Sociedad Española de Oncología Médica y la Sociedad Española de Patología

The treatment of head and neck and salivary gland tumours is complicated and is constantly evolving. Prognostic and predictive indicators of response to treatment are enormously valuable for designing individualized therapies, which justifies their research and validation. Some biomarkers, such as p16, Epstein–Barr virus, PD-L1, androgen receptors and HER-2, are already used routinely in clinical practice. These biomarkers, along with other markers that are currently under development, and the massively parallel sequencing of genes, ensure future advances in the treatment of these neoplasms.In this consensus, a group of experts in the diagnosis and treatment of tumours of the head and neck and salivary glands were selected by the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica – SEAP) and the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica – SEOM) to evaluate the currently available information and propose a series of recommendations to optimize the determination and daily clinical use of biomarkers.(AU)

El tratamiento de los tumores de cabeza y cuello y de glándulas salivales es complejo, y evoluciona de forma constante. Los indicadores pronósticos y predictivos de respuesta al tratamiento son enormemente valiosos para diseñar terapias individualizadas, lo que justifica su investigación y validación. Algunos biomarcadores como p16, el virus de Epstein-Barr, PD-L1, los receptores de andrógenos o HER-2, ya se utilizan de manera rutinaria en la práctica clínica. Estos biomarcadores, junto con otros marcadores que están actualmente en desarrollo, y la secuenciación masiva de genes, aseguran los futuros avances en el tratamiento de estas neoplasias. En este consenso, un grupo de expertos en el diagnóstico y tratamiento de los tumores de cabeza y cuello y glándulas salivales seleccionado por la Sociedad Española de Anatomía Patológica (SEAP) y la Sociedad Española de Oncología Médica (SEOM) evalúan la información actualmente disponible y proponen una serie de recomendaciones para optimizar la determinación y utilización en la práctica clínica diaria de los biomarcadores.(AU)

Collapsing Glomerulonephritis in a Kidney Transplant Recipient after mRNA SARS-CoV-2 Vaccination.

With the vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), studies are describing cases of glomerulonephritis arising after vaccination. We present the first case of a kidney transplant patient who, after mRNA vaccination against SARS-CoV-2, developed nephrotic proteinuria and renal dysfunction, with a biopsy diagnostic of collapsing glomerulonephritis. No other triggers for this glomerulonephritis were identified. Antibodies against the spike protein were negative, but the patient developed a specific T-cell response. The close time between vaccination and the proteinuria suggests a possible determinant role of vaccination. We should be aware of nephropathies appearing after COVID-19 vaccination in kidney transplant recipients also.

Tacrolimus CYP3A Single-Nucleotide Polymorphisms and Preformed T- and B-Cell Alloimmune Memory Improve Current Pretransplant Rejection-Risk Stratification in Kidney Transplantation.

Achieving fast immunosuppression blood exposure after kidney transplantation is key to abrogating both preformed and de novo anti-donor humoral and cellular alloresponses. However, while tacrolimus (TAC) is the cornerstone immunosuppressant inhibiting adaptive alloimmunity, its blood exposure is directly impacted by different single-nucleotide polymorphisms (SNPs) in CYP3A TAC-metabolizing enzymes. Here, we investigated how functional TAC-CYP3A genetic variants (CYP3A4*22/CYP3A5*3) influence the main baseline clinical and immunological risk factors of biopsy-proven acute rejection (BPAR) by means of preformed donor-specific antibodies (DSAs) and donor-specific alloreactive T cells (DSTs) in a large European cohort of 447 kidney transplants receiving TAC-based immunosuppression. A total of 70 (15.7%) patients developed BPAR. Preformed DSAs and DSTs were observed in 12 (2.7%) and 227 (50.8%) patients, respectively. According to the different CYP3A4*22 and CYP3A5*3 functional allele variants, we found 4 differential new clusters impacting fasting TAC exposure after transplantation; 7 (1.6%) were classified as high metabolizers 1 (HM1), 71 (15.9%) as HM2, 324 (72.5%) as intermediate (IM), and 45 (10.1%) as poor metabolizers (PM1). HM1/2 showed significantly lower TAC trough levels and higher dose requirements than IM and PM (p < 0.001) and more frequently showed TAC underexposure (<5 ng/ml). Multivariate Cox regression analyses revealed that CYP3A HM1 and IM pharmacogenetic phenotypes (hazard ratio (HR) 12.566, 95% CI 1.99-79.36, p = 0.007, and HR 4.532, 95% CI 1.10-18.60, p = 0.036, respectively), preformed DSTs (HR 3.482, 95% CI 1.99-6.08, p < 0.001), DSAs (HR 4.421, 95% CI 1.63-11.98, p = 0.003), and delayed graft function (DGF) (HR 2.023, 95% CI 1.22-3.36, p = 0.006) independently predicted BPAR. Notably, a significant interaction between T-cell depletion and TAC underexposure was observed, showing a reduction of the BPAR risk (HR 0.264, 95% CI 0.08-0.92, p = 0.037). Such variables except for DSAs displayed a higher predictive risk for the development of T cell-mediated rejection (TCMR). Refinement of pretransplant monitoring by incorporating TAC CYP3A SNPs with preformed DSAs as well as DSTs may improve current rejection-risk stratification and help induction treatment decision-making.

Recommendations for the use of biomarkers for head and neck cancer, including salivary gland tumours: a consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology.

The treatment of head and neck and salivary gland tumours is complicated and evolves constantly. Prognostic and predictive indicators of response to treatment are enormously valuable for designing individualized therapies, which justifies their research and validation. Some biomarkers, such as p16, Epstein-Barr virus, PD-L1, androgen receptors and HER-2, are already used routinely in clinical practice. These biomarkers, along with other markers that are currently under development, and the massively parallel sequencing of genes, ensure future advances in the treatment of these neoplasms. In this consensus, a group of experts in the diagnosis and treatment of tumours of the head and neck and salivary glands were selected by the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica-SEAP) and the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica-SEOM) to evaluate the currently available information and propose a series of recommendations to optimize the determination and daily clinical use of biomarkers.

Th1 Cytokines Signature in 2 Cases of IgA Nephropathy Flare after mRNA-Based SARS-CoV-2 Vaccine: Exploring the Pathophysiology.

mRNA-based vaccines have dramatically shifted the course of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. IgA nephropathy (IgAN) flare is the most reported renal adverse effect after the administration of these vaccines. Unraveling the mechanistic pathways leading to these flares is necessary to confirm a causal association. Herein, we report 2 cases of IgAN flare after SARS-CoV-2 vaccination in patients previously diagnosed with IgAN. We describe and compare the clinical and analytical features of the disease at the time of the diagnostic with the post-vaccine flare. In addition, we obtained serum and urine of these patients at the moment of the flare and determined the levels of IL-2, TNF-α, and IFNγ using a multiplex bead-based assay. As diseased controls, we included n = 13 patients diagnosed with IgAN who had available serum and urine samples at the moment of the diagnostic stored in our biobank. We also included 6 healthy controls. Compared to the first episode, postvaccination flares were more severe in terms of peak serum creatinine, albuminuria, and urinary erythrocyte count. The histological lesions found at the biopsy performed during the post-vaccine flare were similar to those found at the diagnostic. One of the patients who suffered a post-vaccine flare showed increased serum IL-2 and TNFα compared to the IgAN-diseased controls and the healthy controls. In conclusion, although several cases of post-vaccine IgAN flares have been reported, there are no mechanistic studies on the occurrence of these flares. We here suggest that hyperactivation of the Th1 pathway may be involved, but larger studies with more refined methods for numerical and functional Th1 lymphocytes evaluation are required.

The Isothermal Amplification AmpFire Assay for Human Papillomavirus (HPV) Detection and Genotyping in Formalin-Fixed, Paraffin-Embedded Oropharyngeal Cancer Samples.

Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinomas (OPSCCs) represent a distinct clinical entity compared with HPV-negative tumors with particular regard to treatment response and survival outcome. The aim of this study was to assess the AmpFire Multiplex HR-HPV tests, for the detection and genotyping of 15 high-risk (HR) HPV types in formalin-fixed, paraffin-embedded (FFPE) samples and identify HPV-driven OPSCC. DNA from 160 OPSCC FFPE specimens plus 23 samples from other head and neck primary sites was tested. Results were compared with those obtained using Linear Array HPV-DNA Genotyping Test. Linear Array and AmpFire Multiplex HR-HPV tests showed, for all samples and specifically for OPSCCs, an overall concordance agreement of 98.9% and 99.4% and a Cohen κ coefficient of 0.972 and 0.984, respectively. A concordance of 100% for HPV16 and HPV18 was observed. The overall agreement between p16INK4a overexpression and HPV detection by the AmpFire Multiplex HR-HPV assay in 145 OPSCC samples was 93.8%, with a Cohen κ coefficient of 0.848. The AmpFire HPV Tests are simple assays for detection and genotyping of HPV-DNA in OPSCC FFPE samples and can be easily implemented in the clinical practice setting for HPV-DNA detection.

Acute Tubulointerstitial Nephritis in Clinical Oncology: A Comprehensive Review.

Acute kidney injury in patients who suffer a malignancy is a common complication. Due to its high prevalence and effective treatment, one of the most frequent causes that both oncologists and nephrologists must be aware of is acute tubulointerstitial nephritis (ATIN). ATIN is an immunomediated condition and the hallmark of the disease, with the presence of a tubulointerstitial inflammatory infiltrate in the renal parenchyma. This infiltrate is composed mainly of T lymphocytes that can be accompanied by macrophages, neutrophils, or eosinophils among other cells. One of the major causes is drug-related ATIN, and some antineoplastic treatments have been related to this condition. Worthy of note are the novel immunotherapy treatments aimed at enhancing natural immunity in order to defeat cancer cells. In the context of the immunosuppression status affecting ATIN patients, some pathogen antigens can trigger the development of the disease. Finally, hematological malignancies can also manifest in the kidney leading to ATIN, even at the debut of the disease. In this review, we aim to comprehensively examine differential diagnosis of ATIN in the setting of a neoplastic patient.

Extracapillary proliferation scoring correlates with renal outcome and contributes to stratification in adult patients with immunoglobulin A nephropathy.

BACKGROUND: The revised Oxford classification of diagnostic renal biopsies has been proposed to aid in the prediction of renal outcome. We aimed to validate the histological crescents and interstitial fibrosis and tubular atrophy (IFTA) subgrouping, and to investigate the additional value of the proportion of crescents (CatPE) in the prediction of renal outcome. METHODS: Data were retrospectively collected over 10 years, from the time of diagnosis, by systematic review of medical records from 90 patients with renal biopsies recruited to cohorts from two hospitals in Spain. Patients were classified into three groups for the analysis: CatPE >25% (C2), CatPE <25% (C1) and without this type of lesion (C0). The end point was renal survival defined by either >50% reduction in glomerular filtrate rate or end-stage renal disease. RESULTS: Renal survival at 5 years was 90% in group C0, 81% in group C1 and 31% in group C2 (P = 0.013). The presence of >25% crescents in the sample was associated with more severe disease when compared with <25%, as demonstrated by more interstitial fibrotic change and by lower estimated glomerular filtration rate at diagnosis, as well as worse renal function at 2 and 5 years. At the time of diagnosis and at 24 months, the group with IFTA >50% had poorer renal function compared with the other groups. CONCLUSIONS: We have confirmed the predictive value for renal survival of the revised Oxford classification in a two-centre study. We found worse renal outcome in patients with severe tubulointerstitial fibrosis and atrophy. Patients with extracapillary lesions >25% and IFTA >50% had a worse renal prognosis due to more severe kidney injury. These results contribute to patient stratification in immunoglobulin A nephropathy for therapeutic, epidemiological and basic research.

Nivolumab Plus Ipilimumab for Treatment-Naïve Metastatic Uveal Melanoma: An Open-Label, Multicenter, Phase II Trial by the Spanish Multidisciplinary Melanoma Group (GEM-1402).

PURPOSE: This study aimed to assess the efficacy of the combination of nivolumab (nivo) plus ipilimumab (ipi) as a first-line therapy with respect to the 12-month overall survival (OS) in patients with metastatic uveal melanoma (MUM) who are not eligible for liver resection. METHODS: This was a single-arm, phase II trial led by the Spanish Multidisciplinary Melanoma Group (GEM) on nivo plus ipi for systemic treatment-naïve patients of age > 18 years, with histologically confirmed MUM, Eastern Cooperative Oncology Group-PS 0/1, and confirmed progressive metastatic disease (M1). Nivo (1 mg/kg once every 3 weeks) and ipi (3 mg/kg once every 3 weeks) were administered during four inductions, followed by nivo (3 mg/kg once every 2 weeks) until progressive disease, toxicity, or withdrawal. The primary end point was 12-month OS. OS, progression-free survival (PFS), and overall response rate were evaluated every 6 weeks using RECIST (v1.1). Safety was also evaluated. Logistic regression and Cox proportional hazard models comprising relevant clinical factors were used to evaluate the potential association with response to treatment and survival. Cytokines were quantified in serum samples for their putative role in immune modulation/angiogenesis and/or earlier evidence of involvement in immunotherapy. RESULTS: A total of 52 patients with a median age of 59 years (range, 26-84 years) were enrolled. Overall, 78.8%, 56%, and 32% of patients had liver M1, extra-liver M1, and elevated lactate dehydrogenase. Stable disease was the most common outcome (51.9%). The primary end point was 12-month OS, which was 51.9% (95% CI, 38.3 to 65.5). The median OS and PFS were 12.7 months and 3.0 months, respectively. PFS was influenced by higher LDH values. CONCLUSIONS: Nivo plus ipi in the first-line setting for MUM showed a modest improvement in OS over historical benchmarks of chemotherapy, with a manageable toxicity profile.

Noncanonical immunomodulatory activity of complement regulator C4BP(ß-) limits the development of lupus nephritis.

Lupus nephritis is a chronic autoimmune-inflammatory condition that can lead to end-stage kidney disease. Presently available immunosuppressive treatments for lupus nephritis are suboptimal and can induce significant side effects. Recently, we characterized a novel immunomodulatory activity of the minor isoform of the classical pathway complement inhibitor, C4BP(ß-). We show here that C4BP(ß-) treatment prevented the development of proteinuria and albuminuria, decreased significantly the formation of anti-dsDNA antibodies and, locally, mitigated renal glomerular IgG and C3 deposition and generation of apoptotic cells. There was a consequent histological improvement and increased survival in lupus-prone mice. The therapeutic efficacy of C4BP(ß-) was analogous to that of the broad-acting immunosuppressant cyclophosphamide. Remarkably, a comparative transcriptional profiling analysis revealed that the kidney gene expression signature resulting from C4BP(ß-) treatment turned out to be 10 times smaller than that induced by cyclophosphamide treatment. C4BP(ß-) immunomodulation induced significant downregulation of transcripts relevant to lupus nephritis indicating immunopathogenic cell infiltration, including activated T cells (Lat), B cells (Cd19, Ms4a1, Tnfrsf13c), inflammatory phagocytes (Irf7) and neutrophils (Prtn3, S100a8, S100a9). Furthermore, cytokine profiling and immunohistochemistry confirmed that C4BP(ß-), through systemic and local CXCL13 downregulation, was able to prevent ectopic lymphoid structures neogenesis in aged mice with lupus nephritis. Thus, due to its anti-inflammatory and immunomodulatory activities and high specificity, C4BP(ß-) could be considered for further clinical development in patients with systemic lupus erythematosus.

Clinical features and outcomes in a cohort of patients with immunoglobulin G4-related disease at a university hospital in Spain.

BACKGROUND: Immunoglobulin G4-related disease (IgG4-RD) is a fibro-inflammatory, immune-mediated disorder, which characteristically affects the glandular tissue but has the potential to affect any organ. METHODS: We retrospectively reviewed clinical, laboratory, histological characteristics and treatment response during 12 months of follow-up of a cohort of patients with IgG4-RD diagnosed at a tertiary public hospital. Disease activity was assessed by means of the IgG4-RD responder index (IgG4-RD RI). RESULTS: In all, 15 patients have been diagnosed at our Institution and herein studied (80% men), with a median age of 60.7 years and a mean affectation of 2.8 organs per patient. We identified six patients with definitive diagnosis and nine with possible IgG4-RD, according to the Japanese diagnostic algorithm. IgG4-RD RI decreased from a median of 11.3 at baseline to 4.0 after 6 months and 6.2 after 12 months. Relapse occurred in five patients and was associated with lower cumulative steroid doses. Five patients (33.3%) required additional immunosuppressive (IS) drugs. Five adverse events were seen during follow-up: three infections, one deep vein thrombosis and one gastrointestinal bleeding. One patient died of pneumonia. CONCLUSIONS: IgG4-RD is an inflammatory disease that can affect any organ. Glucocorticoids were an effective first line of treatment; however, this treatment is associated with important adverse events and relapses occurred in patients with low cumulative doses. As an alternative, IS treatment with rituximab could be an interesting option in those patients.

Human papillomavirus in laryngeal and hypopharyngeal lymphoepithelial carcinoma.

The involvement of human papillomavirus (HPV) in laryngeal and hypopharyngeal lymphoepithelial carcinoma was investigated in a series of ten cases (seven laryngeal and three hypopharyngeal), retrieved from the files of three tertiary hospitals in the 2000-2017 period, through polymerase chain reaction with SPF10 primers and INNO-LiPA HPV Genotyping Extra II (Innogenetics). Epstein-Barr virus (EBV) was tested in all cases with in situ hybridization INFORM EBER Probe (Ventana Medical Systems). p16 and p53 expression were immunohistochemically analyzed. Calculated annual incidence was 0.013/100,000, and prevalence was 0.2% of laryngeal and hypopharyngeal carcinomas. All cases were EBV negative. HPV was detected in five cases, three of which also overexpressed p16. HPV16 was detected in four cases, and HPV58 in one case. Five cases were HPV negative, only one of these five overexpressed p16. No recurrence was observed in nine cases during follow-up. The 5-year disease-specific-survival rate was 100%. Mean overall survival was 87 months. Lymphoepithelial carcinoma of the larynx and hypopharynx are not related to EBV. Simultaneous HPV+/p16+ is consistent with HPV causation in a fraction of laryngeal and hypopharyngeal lymphoepithelial carcinomas.

Reproducibility of the Oxford classification of immunoglobulin A nephropathy, impact of biopsy scoring on treatment allocation and clinical relevance of disagreements: evidence from the VALidation of IGA study cohort.

BACKGROUND: The VALidation of IGA (VALIGA) study investigated the utility of the Oxford Classification of immunoglobulin A nephropathy (IgAN) in 1147 patients from 13 European countries. Methods. Biopsies were scored by local pathologists followed by central review in Oxford. We had two distinct objectives: to assess how closely pathology findings were associated with the decision to give corticosteroid/immunosuppressive (CS/IS) treatments, and to determine the impact of differences in MEST-C scoring between central and local pathologists on the clinical value of the Oxford Classification. We tested for each lesion the associations between the type of agreement (local and central pathologists scoring absent, local present and central absent, local absent and central present, both scoring present) with the initial clinical assessment, as well as long-term outcomes in those patients who did not receive CS/IS. RESULTS: All glomerular lesions (M, E, C and S) assessed by local pathologists were independently associated with the decision to administer CS/IS therapy, while the severity of tubulointerstitial lesions was not. Reproducibility between local and central pathologists was moderate for S (segmental sclerosis) and T (tubular atrophy/interstitial fibrosis), and poor for M (mesangial hypercellularity), E (endocapillary hypercellularity) and C (crescents). Local pathologists found statistically more of each lesion, except for the S lesion, which was more frequent with central review. Disagreements were more likely to occur when the proportion of glomeruli affected was low. The M lesion, assessed by central pathologists, correlated better with the severity of the disease at presentation and discriminated better with outcomes. In contrast, the E lesion, evaluated by local pathologists, correlated better with the clinical presentation and outcomes when compared with central review. Both C and S lesions, when discordant between local and central pathologists, had a clinical phenotype intermediate to double absent lesions (milder disease) and double present (more severe). CONCLUSION: We conclude that differences in the scoring of MEST-C criteria between local pathologists and a central reviewer have a significant impact on the prognostic value of the Oxford Classification. Since the decision to offer immunosuppressive therapy in this cohort was intimately associated with the MEST-C score, this study indicates a need for a more detailed guidance for pathologists in the scoring of IgAN biopsies.

Double positivity for HPV-DNA/p16ink4a is the biomarker with strongest diagnostic accuracy and prognostic value for human papillomavirus related oropharyngeal cancer patients.

BACKGROUND: The etiologic role of human papillomaviruses (HPV) in oropharyngeal cancer (OPC) is well established. Nevertheless, information on survival differences by anatomic sub-site or treatment remains scarce, and it is still unclear the HPV-relatedness definition with best diagnostic accuracy and prognostic value. METHODS: We conducted a retrospective cohort study of all patients diagnosed with a primary OPC in four Catalonian hospitals from 1990 to 2013. Formalin-fixed, paraffin-embedded cancer tissues were subjected to histopathological evaluation, DNA quality control, HPV-DNA detection, and p16INK4a/pRb/p53/Cyclin-D1 immunohistochemistry. HPV-DNA positive and a random sample of HPV-DNA negative cases were subjected to HPV-E6*I mRNA detection. Demographic, tobacco/alcohol use, clinical and follow-up data were collected. Multivariate models were used to evaluate factors associated with HPV positivity as defined by four different HPV-relatedness definitions. Proportional-hazards models were used to compare the risk of death and recurrence among HPV-related and non-related OPC. RESULTS: 788 patients yielded a valid HPV-DNA result. The percentage of positive cases was 10.9%, 10.2%, 8.5% and 7.4% for p16INK4a, HPV-DNA, HPV-DNA/HPV-E6*I mRNA, and HPV-DNA/p16INK4a, respectively. Being non-smoker or non-drinker was consistently associated across HPV-relatedness definitions with HPV positivity. A suggestion of survival differences between anatomic sub-sites and treatments was observed. Double positivity for HPV-DNA/p16INK4a showed strongest diagnostic accuracy and prognostic value. CONCLUSIONS: Double positivity for HPV-DNA/p16INK4a, a test that can be easily implemented in the clinical practice, has optimal diagnostic accuracy and prognostic value. Our results have strong clinical implications for patients' classification and handling and also suggest that not all the HPV-related OPC behave similarly.