Purpose: The identification of high-risk patients within human papillomavirus (HPV)-positive and -negative head and neck squamous cell carcinoma (HNSCC) is needed for improved treatment and surveillance strategies. In this study, we set out to discover antibody responses (AR) with prognostic impact in HNSCC stratified by HPV status.Experimental Design: A fluorescent bead-based multiplex serology assay on 29 cancer antigens (16 cancer-testis antigens, 5 cancer-retina antigens, and 8 oncogenes) and 29 HPV antigens was performed in samples of 362 patients with HNSCC from five independent cohorts (153 HPV positive, 209 HPV negative). A multivariable Cox proportional hazard model with bootstrapping (M ¼ 1000) was used for validation of prognostic antibody responses.Results: Antibody response to any of the cancer antigens was found in 257 of 362 patients (71%). In HPV-negative patients, antibody responses to c-myc, MAGE-A1, -A4, and Rhodopsin E2 (combined as AR high risk ) were significantly associated with shorter overall survival. In HPV-positive patients, antibody responses to IMP-1 were discovered as a negative prognostic factor. AR high risk (HR ¼ 1.76) and antibody responses to IMP-1 (HR ¼ 3.28) were confirmed as independent markers for a poor prognosis in a multivariable Cox proportional hazard model with bootstrapping (M ¼ 1000).Conclusions: We identified antibody responses to cancer antigens that associate with a dismal prognosis in patients with HNSCC beyond HPV-positive status. AR high risk may be used to detect HPV-negative patients with an extraordinarily bad prognosis. Most importantly, antibody response to IMP-1 may serve as a marker for a subgroup of HPVpositive patients who present with a poor prognosis similar to that in HPV-negative patients.

Cytokines and immune mediators play an important role in the communication between immune cells guiding their response to infectious diseases or cancer. In this study, a comprehensive longitudinal analysis of serum cytokines and immune mediators in head and neck squamous cell carcinoma (HNSCC) patients was performed. In a prospective, non-interventional, longitudinal study, blood samples from 22 HNSCC patients were taken at defined time points (TP) before, during, and every 3 months after completion of (chemo)radio)therapy (CRT/RT) until 12 months after treatment. Serum concentrations of 17 cytokines/immune mediators and High-Mobility-Group-Protein B1 (HMGB1) were measured by fluorescent bead array and ELISA. Concentrations of sFas were significantly elevated during and after CRT/RT, whereas perforin levels were significantly decreased after CRT/RT. Levels of MIP-1β and Granzyme B differed significantly during CRT/RT by HPV status. Increased HMGB1 levels were observed at recurrence, accompanied by high levels of IL-4 and IL-10. The sFas increase and simultaneous perforin decrease may indicate an impaired immune cell function during adjuvant radiotherapy. Increased levels of pro-inflammatory cytokines in HPV+ compared to HPV− patients seem to reflect the elevated immunogenicity of HPV-positive tumors. High levels of HMGB1 and anti-inflammatory cytokines at recurrence may be interpreted as a sign of immune evasion.

There have been hints that nonviral cancer antigens are differentially expressed in human papillomavirus (HPV)‐positive and HPV‐negative head and neck squamous cell carcinoma (HNSCC). Antibody responses (AR) to cancer antigens may be used to indirectly determine cancer antigen expression in the tumor using a noninvasive and tissue‐saving liquid biopsy. Here, we set out to characterize AR to a panel of nonviral cancer antigens in HPV‐positive and HPV‐negative HNSCC patients. A fluorescent microbead multiplex serology to 29 cancer antigens (16 cancer‐testis antigens, 5 cancer‐retina antigens and 8 oncogenes) and 29 HPV‐antigens was performed in 382 HNSCC patients from five independent cohorts (153 HPV‐positive and 209 HPV‐negative). AR to any of the cancer antigens were found in 272/382 patients (72%). The ten most frequent AR were CT47, cTAGE5a, c‐myc, LAGE‐1, MAGE‐A1, ‐A3, ‐A4, NY‐ESO‐1, SpanX‐a1 and p53. AR to MAGE‐A3, MAGE‐A9 and p53 were found at significantly different prevalences by HPV status. An analysis of AR mean fluorescent intensity values uncovered remarkably different AR clusters by HPV status. To identify optimal antigen selections covering a maximum of patients with ≤10 AR, multiobjective optimization revealed distinct antigen selections by HPV status. We identified that AR to nonviral antigens differ by HPV status indicating differential antigen expression. Multiplex serology may be used to characterize antigen expression using serum or plasma as a tissue‐sparing liquid biopsy. Cancer antigen panels should address the distinct antigen repertoire of HPV‐positive and HPV‐negative HNSCC.

BackgroundExosomes contribute to immunosuppression in head and neck squamous cell carcinoma (HNSCC), a tumor entity which lacks specific tumor biomarkers. Plasma-derived exosomes from HNSCC patients correlate with clinical parameters and have potential as liquid biopsy. Here, we investigate the cargo and functional profile of saliva-derived exosomes from HNSCC patients and their potential as non-invasive biomarkers for disease detection and immunomodulation.MethodsExosomes were isolated from saliva of HNSCC patients (n = 21) and healthy donors (HD, n = 12) by differential ultracentrifugation. Surface values of immune checkpoints and tumor associated antigens on saliva-derived exosomes were analyzed by bead-based flow cytometry using CD63 capture. Upon co-incubation with saliva-derived exosomes, activity and proliferation of T cells were assessed by flow cytometry (CD69 expression, CFSE assay). Adenosine levels were measured by mass spectrometry after incubation of saliva-derived exosomes with exogenous ATP. miRNA profiling of saliva-derived exosomes was performed using the nCounter® SPRINT system.ResultsSaliva-derived, CD63-captured exosomes from HNSCC patients carried high amounts of CD44v3, PDL1 and CD39. Compared to plasma, saliva was rich in tumor-derived, CD44v3+ exosomes and poor in hematopoietic cell-derived, CD45+ exosomes. CD8+ T cell activity was attenuated by saliva-derived exosomes from HNSCC patients, while proliferation of CD4+ T cells was not affected. Further, saliva-derived exosomes produced high levels of immunosuppressive adenosine. 62 HD- and 31 HNSCC-exclusive miRNAs were identified. Samples were grouped in “Healthy” and “Cancer” based on their saliva-derived exosomal miRNA profile, which was further found to be involved in RAS/MAPK, NF-κB complex, Smad2/3, and IFN-α signaling.ConclusionsSaliva-derived exosomes from HNSCC patients were enriched in tumor-derived exosomes whose cargo and functional profile reflected an immunosuppressive TME. Surface values of CD44v3, PDL1 and CD39 on CD63-captured exosomes, adenosine production and the miRNA cargo of saliva-derived exosomes emerged as discriminators of disease and emphasized their potential as liquid biomarkers specific for HNSCC.

Programmed‐death‐1 (PD1) antibodies are approved for recurrent and metastatic head and neck squamous cell carcinoma. Multiple drugs targeting costimulatory and coinhibitory immune checkpoint molecules (ICM) have been discovered. However, it remains unknown how these ICM are affected by curative conventional therapy on different immune cell subsets during the course of treatment. In the prospective noninterventional clinical study titled “Immune Response Evaluation to Curative conventional Therapy” (NCT03053661), 22 patients were prospectively enrolled. Blood samples were drawn at defined time points throughout curative conventional treatment and follow‐up. Immune cells (IC) from the different time points were assessed by multicolor flow cytometry. The following ICM were measured by flow cytometry: PD1, CTLA4, BTLA, CD137, CD27, GITR, OX40, LAG3 and TIM3. Dynamics of ICM expression were assessed using nonparametric paired samples tests. Significant changes were noted for PD1, BTLA and CD27 on multiple IC types during or after radiotherapy. Nonsignificant trends for increased expression of OX40 and GITR from baseline until the end of RT were observed on CD4 T cells and CD4+ CD39+ T cells. In patients with samples at recurrence of disease, a nonsignificant increase of TIM3 and LAG3 positive CD4+ CD39+ T cells was evident, accompanied by an increase of double positive cells for TIM3/LAG3. Potential future targets to be combined with RT in the conventional treatment and anti‐PD1/PD‐L could be BTLA agonists, or agonistic antibodies to costimulatory ICM like CD137, OX40 or GITR. The combination of cetuximab with CD27 agonistic antibodies enhancing ADCC or the targeting of TIM3/LAG3 may be another promising strategy.