Nivolumab as a Promising Treatment Option for Metastatic Salivary Duct Carcinoma.

Salivary duct carcinomas (SDC) of the parotid gland are rarely occurring highly malignant tumors. A 65-year-old man presented with a preauricular mass. After surgical treatment and histologic examination, the findings were interpreted as a squamous cell carcinoma (SCC) metastasis of the parotid gland deriving from a cancer of unknown primary DD primary SCC of the parotid gland. Adjuvant platinum-based radiochemotherapy was administered in domo. However, re-staging revealed multiple size-progressive pulmonary round lesions. After resection and histological examination of a pulmonary mass and in synopsis with the primary tumor, the initial diagnosis of SCC was revised to SDC of the parotid gland. With positive HER-2 status, off-label trastuzumab/docetaxel was initiated in an individual healing attempt, during which the pulmonary metastases showed clear progression. Consequently, the patient received immunotherapy with nivolumab according to his negative PD-L1 status. After 57 cycles of nivolumab, the patient presents with partial remission and in good condition. We report, for the first time, a robust response of metastatic SDC to checkpoint inhibition with nivolumab without additional radiotherapy.

Risk factors for immune-related adverse effects during CPI therapy in patients with head and neck malignancies - a single center study.

Introduction: Checkpoint inhibitors, such as PD1 inhibitors, represent an important pillar in the therapy of advanced malignancies of the head and neck region. The most relevant complications are immune-related adverse effects (irAEs), which represent an immense burden for patients. Currently, no sufficient stratification measures are available to identify patients at increased risk of irAEs. The aim of this retrospective study was to examine whether demographic, histopathological, clinical, or laboratory values at the start of CPI therapy represent a risk factor for the later occurrence of autoimmune complications. Material and methods: Data from 35 patients between 2018 and 2021 who received therapy with nivolumab or pembrolizumab for head and neck malignancy were analyzed and assessed for any associations with the subsequent occurrence of irAEs. Results: IrAE developed in 37% of patients, with pneumonitis being the most common form (14%). Pneumonitis was found in patients with an average significantly lower T-stage of primary tumors. An increase in basophilic leukocytes was found in patients with dermatitis later in the course. When thyroiditis developed later, the patients had a higher CPS score and lower monocyte levels. Discussion: Even though individual laboratory values at the beginning of therapy might show a statistical association with the later occurrence of irAEs, neither demographic, histopathological, nor laboratory chemistry values seem to be able to generate a sound and reliable risk profile for this type of complication. Therefore, patients need to be educated and sensitized to irAEs, and regular screening for irAEs should be carried out.

Plasma-derived small extracellular vesicles unleash the angiogenic potential in head and neck cancer patients.

BACKGROUND: In Head and neck cancer (HNC) angiogenesis is essential for tumor progression and metastasis. Small extracellular vesicles (sEVs) from HNC cell lines alter endothelial cell (EC) functions towards a pro-angiogenic phenotype. However, the role of plasma sEVs retrieved from HNC patients in this process is not clear so far. METHODS: Plasma sEVs were isolated on size exclusion chromatography columns from 32 HNC patients (early-stage UICC I/II: 8, advanced-stage UICC III/IV: 24), 12 patients with no evident disease after therapy (NED) and 16 healthy donors (HD). Briefly, sEVs were characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), BCA protein assays and Western blots. Levels of angiogenesis-associated proteins were determined using antibody arrays. The interaction of fluorescently-labeled sEVs with human umbilical vein ECs was visualized by confocal microscopy. The functional effect of sEVs on tubulogenesis, migration, proliferation and apoptosis of ECs was assessed. RESULTS: The internalization of sEVs by ECs was visualized using confocal microscopy. Based on antibody arrays, all plasma sEVs were enriched in anti-angiogenic proteins. HNC sEVs contained more pro-angiogenic MMP-9 and anti-angiogenic proteins (Serpin F1) than HD sEVs. Interestingly, a strong inhibition of EC function was observed for sEVs from early-stage HNC, NED and HD. In contrast, sEVs from advanced-stage HNC showed a significantly increased tubulogenesis, migration and proliferation and induced less apoptosis in ECs than sEVs from HD. CONCLUSIONS: In general, plasma sEVs carry a predominantly anti-angiogenic protein cargo and suppress the angiogenic properties of ECs, while sEVs from (advanced-stage) HNC patients induce angiogenesis compared to HD sEVs. Thus, tumor-derived sEVs within the plasma of HNC patients might shift the angiogenic switch towards angiogenesis.

The effects of COVID-19 on the vestibular system.

Introduction: The symptoms and severity of SARS-CoV-2 infection vary greatly across the spectrum, from asymptomatic infection to severe pneumonia with acute respiratory distress syndrome and even death. Dizziness is a frequently reported symptom of SARS-CoV-2 viral infection. However, the extent to which this symptom results from the effect of SARS-CoV-2 on the vestibular system remains unclear. Materials and methods: In the present single-center, prospective cohort study, patients with a previous SARS-CoV-2 infection underwent a vestibular assessment consisting of the Dizziness Handicap Inventory to assess dizziness during and after infection, a clinical examination, the video head impulse test, and the subjective visual vertical test. When the subjective visual vertical test result was abnormal, vestibular-evoked myogenic potentials were performed. Vestibular testing results were compared to pre-existing normative data of healthy controls. In addition, we performed a retrospective data analysis of patients admitted to hospital presenting with acute symptoms of dizziness who were also diagnosed with acute SARS-CoV-2 infection. Results: A total of 50 participants have been enrolled. During and after the SARS-CoV-2 infection, women were significantly more likely than men to suffer from dizziness. A significantly reduced semicircular canal or otolith function was not observed in either women or men. Acute SARS-CoV-2 infection was diagnosed in nine patients who presented to the emergency room with acute vestibular syndrome. Six of the patients exhibited acute unilateral peripheral vestibulopathy upon diagnosis. A different patient was diagnosed with vestibular migraine, and two individuals had a posterior inferior cerebellar artery infarct revealed by magnetic resonance imaging. Discussion/conclusion: Overall, a persisting structural affection of the vestibular system by SARS-CoV-2 seems to be unlikely and could not be confirmed by vHIT, SVV, and VEMPS in our study. It seems possible but unlikely that SARS-CoV-2 induces acute vestibulopathy. Nevertheless, dizziness is a common symptom in patients with COVID-19, which should be taken and worked through seriously.

Anosmia Testing as Early Detection of SARS-CoV-2 Positivity; A Prospective Study under Screening Conditions.

Sudden onset of anosmia is a phenomenon often associated with developing COVID-19 disease and has even been described as an initial isolated symptom in individual cases. In this case-control study, we investigated the feasibility of this condition as a suitable screening test in a population at risk. We performed a prospective study with a total of 313 subjects with suspected SARS-CoV-2 infection. In parallel to routine PCR analysis, a modified commercial scent test was performed to objectify the presence of potential anosmia as a predictor of SARS-CoV-2 positivity. Furthermore, a structured interview assessment of the participants was conducted. A total of 12.1% of the study participants had molecular genetic detection of SARS-CoV-2 infection in the nasopharyngeal swab. It could be demonstrated that these subjects had a significantly weaker olfactory identification performance of the scents. Further analysis of the collected data from the scent test and medical history via random forest (Boruta) algorithm showed that no improvement of the prediction power was achieved by this design. The assay investigated in this study may be suitable for screening general olfactory function. For the screening of COVID-19, it seems to be affected by too many external and internal biases and requires too elaborate and selective pre-test screening.

Targeted Treatment of HPV16-positive and -negative SCC Cells With Small Molecule Tyrosine Kinase Inhibitors and Everolimus Affects MMP2 and MMP14 Expression.

BACKGROUND/AIM: The rise of targeted therapies in the treatment of head and neck squamous cell carcinoma (HNSCC) has considerably widened the treatment range. Matrix metalloproteinases (MMPs) are key regulators of the tumor development of many cancer entities, which makes them a promising target for new treatment options. We examined the expression patterns of MMP2 and MMP14 in human papillomavirus (HPV)-positive and -negative SCC lines after treatment with small molecule tyrosine kinase inhibitors (TKIs) and a mechanistic target of rapamycin (mTOR) inhibitor in vitro. MATERIALS AND METHODS: Cells of two human HPV-negative cell lines (UMSCC-11A/-14C) and one HPV-positive cell line (CERV196) were incubated with 20 µmol/l of erlotinib, gefitinib, nilotinib, dasatinib, or everolimus for 24-96 h. Cell proliferation was assessed by proliferation assay and the protein concentrations of MMP2 and MMP14 by sandwich enzyme-linked immunosorbent assay. For statistical analysis, the results were compared with those of untreated SCC cells. RESULTS: MMP2 and MMP14 were expressed in all three tested cell lines; expression levels were highest in the UMSCC-14C cell line. The tested TKIs significantly (p<0.05) reduced MMP2 expression in the UMSCC-14C cell line. In the HPV-positive cell line, the drugs led to an increase in MMP2 and MMP14 expression. CONCLUSION: Dysregulations in MMP signaling are involved in tumorigenesis and metastasis of HNSCCs; MMP2 has been noted as a potential biomarker. The expression of MMP2 and MMP14 is influenced effectively by small molecule TKIs and everolimus. Based on our data, future research should concentrate on a better understanding of the interplay between tumor microenvironment and tumor cells in vitro and in vivo.

Prognostic Factors for the Therapeutic Performance of Cisplatin in Head and Neck Malignancies.

Introduction: For squamous cell carcinoma of the head and neck (HNSCC), cisplatin is used as primary or adjuvant (radio)chemotherapy. In terms of dosage, two main regimens are used, weekly 40mg/m2 or 3-weekly 100mg/m2. For an optimal outcome, the highest possible cumulative total dose of cisplatin is aimed for. The selection of the scheme is patient-specific, but the factors for the selection of the optimal scheme have not yet been conclusively researched. The aim of this study was to find correlations between initial laboratory values and the cumulative total dose of cisplatin, as well as any correlations between early laboratory values or their dynamics and later laboratory values or their dynamics to provide support in the selection of the chemo regimen. Material and Methods: In this retrospective study, the clinical data and laboratory values, namely glomerular filtration rate (GFR), hemoglobin, albumin, leucocyte, erythrocyte and platelet count, over the course of time of 79 patients with HNSCC who had received chemotherapy with cisplatin in our clinic between 2018 and 2021 were evaluated. Results: Patients on 3-weekly regimens achieved a higher mean cumulative total dose of cisplatin than patients on weekly regimens (214.18 ± 65.95 vs 183.33 ± 65.2 mg/m2). Significant positive correlations were seen for total cumulative dose of cisplatin with initial GFR (p=0.001, Pearson's r=0.364), initial hemoglobin (p=0.035, r=0.237), initial erythrocyte (p=0.002, r=0.337), and initial albumin (p=0.002, r=0.337). There were no significant correlations for initial leucocyte or platelets. Regarding the dynamics of the laboratory values under the first chemo administration, no correlation was found with later laboratory values or dynamics. Discussion and Conclusion: As in other prospective studies, our retrospective analysis found a higher cumulative total dose in the 3-weekly regimen. As this seems to correlate positively with patient outcome, superiority of the 3-weekly regimen over the weekly regimen can be assumed. Functioning organ systems, especially of the bone marrow and kidneys, are associated with an increased cumulative total dose and can therefore be regarded as predictive factors. Regular monitoring of laboratory values is nevertheless essential throughout the entire course of chemotherapy.

Post-COVID-19 Impairment of the Senses of Smell, Taste, Hearing, and Balance.

BACKGROUND: Various symptoms have been associated with COVID-19, but little is known about the impacts of COVID-19 on the sensory system, risk factors, and the duration of symptoms. This study assesses olfactory, gustatory, hearing, and vestibular systems after COVID-19. METHODS: This cross-sectional, single-center study involved 50 patients one to six months after COVID-19 and reports their patient records and the extent, onset, and duration of olfactory, gustatory, hearing, and balance disorders using questionnaires during and after COVID-19. Sensory symptoms were objectively studied using the following clinical tests after COVID-19 Sniffin' Sticks, taste tests, tone/speech audiometry, and video head impulse test. RESULTS: Post-COVID-19-patients were suffering from olfactory and gustatory impairment for up to six months. According to the Dizziness Handicap Inventory, balance disorders were less noticed: Overall, about 40% of the patients during COVID-19 and nearly all patients recovered within six months. After COVID-19, clinical tests revealed that 75% were suffering from hyposomnia/anosmia, and 20% of all patients reported mild hypogeusia for up to six months. Vestibular disorders and hearing impairment rarely/did not occur. Females were significantly more affected by sensory impairments than males. CONCLUSIONS: COVID-19 particularly caused olfactory and gustatory impairment; balance disorders were present too; vestibular and auditory symptoms were negligible.

[Validity of SARS-CoV-2 swabs taken preoperatively in children]. / Validität präoperativ entnommener SARS-CoV-2-Abstriche bei Kindern.

BACKGROUND: Due to the limited compliance, the technically correct collection of a pooled nasopharyngeal swab is significantly more difficult in children. Especially during operations in the area of the upper respiratory tract, there is a significantly increased risk of infection with COVID-19 for everyone present in the operating room. The aim of the study is to analyze the validity of SARS-CoV-2 swabs taken preoperatively under suboptimal conditions. MATERIAL AND METHODS: Retrospective comparison of the PCR results of SARS-CoV-2 swaps taken preoperatively and intraoperatively from 62 children in the period from April to July 2020. Median age was 4.49 years. The PCR diagnosis was carried out one or two days preoperatively (in the case of emergency interventions on the same day) and again intraoperatively using a pooled nasopharyngeal swab. RESULTS: All 62 preoperatively taken swabs were negative. Deviating from the preoperative test result, one intraoperatively obtained swab was positive. CONCLUSIONS: Due to limited compliance, a correct preoperative swab technique (preanalytics) cannot always be assumed for children. Sufficient protective measures for everyone present in the operating room are therefore imperative. Intraoperative test should be considered if the preoperative test was performed under difficult conditions.

[Professional teamwork and communication in the operating room-A narrative review]. / Professionelle Teamarbeit und Kommunikation im Operationssaal ­ Eine narrative Übersicht.

BACKGROUND: A team in the operating room (OR) is a hierarchically structured, gender-mixed group of people belonging to different professional categories. Disparities in the objectives of the different team members under economic pressure to perform, are sources of potential conflict in the daily work routine. This may have a negative impact on patient safety and commercial efficiency of hospital management. OBJECTIVE: The aim of this summary is to sensitize the reader to the complex of problems in daily life in the OR and to increase awareness of possible approaches to solve the difficulties in an OR. Problem solutions might be approached by improvement of communication and team building. METHODS: Narrative review of current literature and expert recommendations by a literature search in PubMed and Medline; keywords included teamwork, communication, operating room, team building. RESULTS AND CONCLUSION: Communication and teamwork in the OR are of immense importance for patient safety and the economic development of a hospital. Improvements in communication structure, among other things due to the implementation of a team time out and moderation from outside (OR manager) offer solutions to avoid conflicts in everyday clinical practice.

[Differential diagnosis of intraorbital masses - a narrative review]. / Differentialdiagnostik intraorbitaler Raumforderungen ­ eine Übersicht.

OBJECTIVE: Intraorbital masses represent a condition that is frequently threatening for the visual system. A rigorous differential diagnosis is essential to promptly initiate appropriate therapy and optimize prognosis. MATERIALS/METHODS: Narrative review of current literature and expert recommendations. For further illustration we describe the case of a 71-year-old male admitted to our department three months after sinus surgery. Postoperative intraorbital hematoma of the right orbit had been treated conservatively with antibiotics/corticosteroids, leading to a near-complete unilateral visual loss. The immediate surgical intervention aimed at decompression of the orbit and the optical nerve. Due to the delay, the intervention could not prevent formation of a lipogranuloma. Inflammatory phases associated with the lipogranuloma are successfully managed by conservative treatment based on multidisciplinary recommendations. RESULTS: In the case reported, delay of surgical therapy acted as a cause of intraorbital lipogranuloma formation. Literature supports our recommendation of immediate surgical intervention in case of acute retrobulbar hematoma. Besides acute conditions, intraorbital masses can be a sign of systemic disease. In every case, a multidisciplinary therapeutic approach is required for adequate management. CONCLUSIONS: Intraorbital masses can occur as a complication of trauma or e.g. sinus surgery. On the other hand they can be a sign of systemic disease. Timely diagnosis and treatment prevents from visual loss. That is why rigorous differential diagnosis is essential for every discipline managing intraorbital lesions.

Prevalence of subjective impairments of the sense of smell and taste in employees of retirement and nursing homes during SARS-CoV-2 pandemic.

AIM: To investigate the usability of querying subjective impairments of the sense of smell and taste in order to improve pre-test probability in testing for SARS-CoV-2. To achieve this, exploring the prevalence of these restrictions in the COVID-19-negative population, as well as nasal co-symptoms. DESIGN: A cross-sectional study was carried out as part of the secondary prophylaxis, following the STROBE guidelines of the EQUATOR network. METHODS: In total, 1,734 employees of retirement and nursing homes were tested for COVID-19 and asked for subjective reduction or loss in the sense of smell and taste, furthermore about nasal co-symptoms such as nasal obstruction and rhinorrhoea. RESULTS: All employees tested negative for COVID-19. Subjective hyposmia and hypogeusia rarely occurred and were usually accompanied by other nasal symptoms such as nasal obstruction. Querying subjective hyposmia/anosmia or hypogeusia/ageusia appears to be a useful anamnestic instrument for the clinical assessment of the probability of SARS-CoV-2 infection.

Case Report: Bilateral Palsy of the Vocal Cords After COVID-19 Infection.

During the COVID-19 pandemic, adverse neurological effects have been described. In addition to unspecific neurological symptoms, cranial nerve deficits have appeared as part of SARS-CoV-2 infection. In this case report, we describe a 74-year-old patient who developed bilateral paralysis of the vocal cords some weeks following his dismissal in stable condition after COVID-19 pneumonia. After ruling out central lesions, peripheral tumors, and other possible causes, therapy was initiated with methylprednisolone, inhalations, and oxygen. The patient showed no improvement, so laterofixation after Lichtenberger was performed. The dyspnea worsened after several weeks, so a laser posterior cordectomy was performed with satisfactory outcome.

[The tumor stem cell niche of head and neck - point of intersection with therapeutic potential?] / Die Tumorstammzellnische im Kopf-Hals-Bereich ­ Knotenpunkt mit therapeutischem Potenzial?

An increasing amount of evidence suggests the existence of a stem cell-like population in head and neck squamous cell carcinoma (HNSCC). These cells have been termed cancer stem cells (CSC) due to the shared properties with somatic stem cells, such as the ability to self-renew and differentiate. Furthermore, the CSC are thought to be resistant to antineoplastic treatments and are therefore clinically relevant. As with somatic stem cells, CSC are thought to reside in a specialized supportive microenvironment, called the stem cell niche. One possible strategy to target the CSC could be through affecting functions of the stem cell niche.Stromal cell-derived factor-1 (SDF-1) is a multifunctional cytokine, which is secreted by e. g. stromal cells within the niche. SDF-1 is known to be the major regulator of stem cell trafficking between the niche and the peripheral vascular system. It elicits the chemotactic activity through interaction with a transmembrane receptor CXCR4, expressed by CSC. The SDF-1-CXCR4-axis is thought to play a crucial role in the interaction between CSC and their supportive cells in the tumor niche. A better understanding of these interactions could help in gaining further insight into the pathophysiology of progression/recurrence of malignant diseases and aid in finding new strategies for therapy.Specialized cell culture models are of advantage for deciphering the mechanisms of interaction between CSC and their niche. We anticipate that the recent technological advancements in bioprinting and the development of complex 3D cell culture model systems will contribute to our understanding of these mechanisms and to the establishment of individualized therapies.Here were provide an overview of the current knowledge on the CSC-tumor stem cell niche interactions in HNSCC with a focus on the SDF-1-CXCR4 axis.

FGF Expression in HPV16-positive and -negative SCC After Treatment With Small-molecule Tyrosine Kinase Inhibitors and Everolimus.

BACKGROUND: Targeted therapies in the treatment of head and neck squamous cell carcinoma (HNSCC) are subject to extensive research. Different mutations of genes belonging to the fibroblast growth factor (FGF) family have been detected in HNSCC. In this study, we examined the expression of FGF1 and FGF2 after treatment with small-molecule tyrosine kinase inhibitors (TKIs) and an inhibitor of mechanistic target of rapamycin (mTOR) in vitro using human papillomavirus (HPV)-positive and -negative SCC lines. MATERIALS AND METHODS: Cells of two human HPV-negative cell lines (UMSCC-11A/-14C) and one HPV-positive cell line (CERV196) were incubated with 20 µmol/l of erlotinib, gefitinib, nilotinib, dasatinib, or everolimus for 24-96 h. Cell proliferation was assessed by proliferation assay and the protein concentrations of FGF1 and FGF2 by sandwich enzyme-linked immunosorbent assay. For statistical analysis, the results were compared with those for untreated HPV-negative SCC cells. RESULTS: FGF1 and FGF2 were detected in all three tested cell lines. The tested TKIs significantly (p<0.05 reduced) FGF1 expression in the UMSCC-11A cell line within the first 24 h. At later time points, the tested TKIs and everolimus significantly (p<0.05) increased FGF1 and FGF2 expression in HPV-negative and -positive cancer cell lines. The effect was stronger in the HPV-positive cell line. CONCLUSION: Alterations in FGF signalling are considered to be relevant drivers of tumourigenesis in some HNSCCs. Our results show that the expression of FGF1 and -2 can be influenced effectively by small-molecule TKIs and everolimus. Based on our data, future research should include combinations of specific FGF inhibitors, mTOR inhibitors and other TKIs in the treatment of HNSCC and research on FGF-mediated drug escape mechanisms.

Effect of Small-molecule Tyrosine Kinase Inhibitors on PDGF-AA/BB and PDGFRα/ß Expression in SCC According to HPV16 Status.

BACKGROUND: Despite extensive research into new treatment options, the prognosis for head and neck squamous cell carcinoma remains poor. Platelet-derived growth factor (PDGF) is up-regulated in HNSCC and expression levels decrease after surgery, suggesting its role in tumour development. The influence of HPV on the PDGF/PDGF receptor (PDGFR) pathway remains unclear. In this study, we investigated the effect of small-molecule tyrosine kinase inhibitors (TKIs) on the expression of PDGF and its receptor in vitro using squamous cancer cell lines with different human papillomavirus 16 (HPV16) status. MATERIALS AND METHODS: Two human HPV16-negative cell lines (UMSCC-11A/-14C) and one HPV16-positive cell line (CERV196) were used. Tumour cells were incubated with 20 µmol/l of TKIs nilotinib, dasatinib, afatinib, gefitinib and erlotinib for 24-96 h. Cell proliferation was assessed via proliferation assay and protein concentrations of PDGF-AA and BB and PDGFRα and -ß via sandwich enzyme-linked immunosorbent assay. For statistical analysis, the results were compared with those from an untreated negative control. RESULTS: PDGF-AA/BB and PDGFRα/-ß were detected in all three tested cell lines. The addition of TKI led to a significant (p<0.05) decrease of PDGF/PDGFR at different time points and cell lines. The strongest effects were seen for the expression of PDGF-AA, which was consistently inhibited by most drugs. The effects of the TKI were independent of the HPV status. CONCLUSION: Proteins of this pathway can effectively be inhibited by small molecule TKIs. PDGF-AA seems to be a promising target for future studies with selective TKIs.

Metastasis of pulmonary adenocarcinoma to the palatine tonsil.

Lung cancer rarely metastasizes to the palatine tonsil. There have only been a few cases that have reported on palatine tonsillar metastases of pulmonary adenocarcinoma. In the majority of these cases the primary diagnosis is a small cell lung cancer. The present case report resents an unusual case of a 66-year-old woman with a multiple metastasized lung adenocarcinoma, which was finally detected by tonsillectomy. The present case report and review of the literature revealed the importance of complete and systematic tumor staging, including the examination of the oral cavity in case of lung cancer and that the evident tentative diagnosis is not always the right one.

Communicate or Die - A Model for HPV+ and HPV- CSCs and Their Interactions with SDF-1α.

BACKGROUND/AIM: Cancer stem cells (CSCs) are suspected of being a reason for limited therapy in head and neck squamous cell carcinoma (HNSCC). Stromal cell-derived factor-1α (SDF-1α) plays a critical role in the communication between CSCs and their microenvironment. We investigated the influence of SDF-1α on HPV+/HPV- SCC cell lines to find an approach of explanation for the superior prognosis of HPV+ HNSCCs. MATERIALS AND METHODS: We evaluated the expression of CD44/CXCR4 on HPV+/HPV- SCC cell lines and monitored the influence of SDF-1α on proliferation, morphology and migration of HPV+/HPV- SCCs. RESULTS: HPV- SCCs showed a significant increase of podia formation and an intensified migration towards SDF-1α. HPV+ SCCs rested nearly unaffected by SDF-1α. CONCLUSION: Weakened reaction to SDF-1α in HPV+ SCC could lead to an impaired communication between CSCs and their niche, that would result in an increased exposure of CSCs to the harming influence of e.g. chemotherapeutic agents.