TGFß carrying exosomes in plasma: potential biomarkers of cancer progression in patients with head and neck squamous cell carcinoma.

OBJECTIVES: Contributions of TGFß to cancer progression are well documented. However, plasma TGFß levels often do not correlate with clinicopathological data. We examine the role of TGFß carried in exosomes isolated from murine and human plasma as a contributor to disease progression in head and neck squamous cell carcinoma (HNSCC). MATERIALS AND METHODS: The 4-nitroquinoline-1-oxide (4-NQO) mouse model was used to study changes in TGFß expression levels during oral carcinogenesis. In human HNSCC, TGFß and Smad3 protein expression levels and TGFB1 gene expression were determined. Soluble TGFß levels were evaluated by ELISA and TGFß bioassays. Exosomes were isolated from plasma using size exclusion chromatography, and TGFß content was quantified using bioassays and bioprinted microarrays. RESULTS: During 4-NQO carcinogenesis, TGFß levels in tumour tissues and in serum increased as the tumour progressed. The TGFß content of circulating exosomes also increased. In HNSCC patients, TGFß, Smad3 and TGFB1 were overexpressed in tumour tissues and correlated with increased soluble TGFß levels. Neither TGFß expression in tumours nor levels of soluble TGFß correlated with clinicopathological data or survival. Only exosome-associated TGFß reflected tumour progression and correlated with tumour size. CONCLUSIONS: Circulating TGFß+ exosomes in the plasma of patients with HNSCC emerge as potential non-invasive biomarkers of disease progression in HNSCC.

Tumor gene signatures that correlate with release of extracellular vesicles shape the immune landscape in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinomas (HNSCCs) evade immune responses through multiple resistance mechanisms. Extracellular vesicles (EVs) released by the tumor and interacting with immune cells induce immune dysfunction and contribute to tumor progression. This study evaluates the clinical relevance and impact on anti-tumor immune responses of gene signatures expressed in HNSCC and associated with EV production/release. Expression levels of two recently described gene sets were determined in The Cancer Genome Atlas Head and Neck Cancer cohort (n = 522) and validated in the GSE65858 dataset (n = 250) as well as a recently published single-cell RNA sequencing dataset (n = 18). Clustering into HPV(+) and HPV(-) patients was performed in all cohorts for further analysis. Potential associations between gene expression levels, immune cell infiltration, and patient overall survival were analyzed using GEPIA2, TISIDB, TIMER, and the UCSC Xena browser. Compared to normal control tissues, vesiculation-related genes were upregulated in HNSCC cells. Elevated gene expression levels positively correlated (P < 0.01) with increased abundance of CD4(+) T cells, macrophages, neutrophils, and dendritic cells infiltrating tumor tissues but were negatively associated (P < 0.01) with the presence of B cells and CD8(+) T cells in the tumor. Expression levels of immunosuppressive factors NT5E and TGFB1 correlated with the vesiculation-related genes and might explain the alterations of the anti-tumor immune response. Enhanced expression levels of vesiculation-related genes in tumor tissues associates with the immunosuppressive tumor milieu and the reduced infiltration of B cells and CD8(+) T cells into the tumor.

Editorial: Special Issue on "The Role of Exosomes in Cancer Diagnosis and Therapy".

As a result of extensive research in recent years, small extracellular vesicles (sEVs), also known as exosomes, are now considered major contributors to intercellular communication in health and disease [...].

Expression and Regulatory Mechanisms of MicroRNA in Cholesteatoma: A Systematic Review.

Cholesteatoma is a temporal bone disease characterized by dysfunctions of keratinocytes. MicroRNAs (miRNAs) are evolutionary conserved noncoding RNAs that regulate mRNA expression. They can be packaged into exosomes and transported to target cells that can be used in the future therapy of cholesteatoma. This study aimed to collect knowledge on the role of miRNAs and exosomal miRNAs in cholesteatoma and was conducted according to the PRISMA guidelines for systematic reviews. Four databases were screened: Pubmed/MEDLINE, Web of Science, Scopus, and the Cochrane Library. The last search was run on the 6th of June 2023. We included full-text original studies written in English, which examined miRNAs in cholesteatoma. The risk of bias was assessed using the Office of Health Assessment and Translation (OHAT) Risk of Bias Rating Tool, modified for the needs of this review. We identified 118 records and included 18 articles. Analyses revealed the downregulation of exosomal miR-17 as well as miR-10a-5p, miR-125b, miR-142-5p, miR34a, miR-203a, and miR-152-5p and the overexpression of exosomal miR-106b-5p as well as miR-1297, miR-26a-5p, miR-199a, miR-508-3p, miR-21-3p, miR-584-5p, and miR-16-1-3p in cholesteatoma. The role of differentially expressed miRNAs in cholesteatoma, including cell proliferation, apoptosis, the cell cycle, differentiation, bone resorption, and the remodeling process, was confirmed, making them a potential therapeutic target in this disease.

BMSC-HNC Interaction: Exploring Effects on Bone Integrity and Head and Neck Cancer Progression.

In recent research, the tumor microenvironment has been shown to attract mesenchymal stromal cells (MSCs), which is of particular interest due to its implications for cancer progression. The study focused on understanding the interaction between bone marrow-derived MSCs (BMSCs) and head and neck cancer (HNC) cells. This interaction was found to activate specific markers, notably the osteogenic marker alkaline phosphatase and the oncogene Runx2. These activations corresponded with the release of collagenase enzymes, MMP9 and MMP2. To gain insights into bone resorption related to this interaction, bovine bone slices were used, supporting the growth of "heterogeneous spheroids" that contained both BMSCs and HNC cells. Through scanning electron microscopy and energy-dispersive X-ray (EDX) analysis, it was observed that these mixed spheroids were linked to a notable increase in bone degradation and collagen fiber exposure, more so than spheroids of just BMSCs or HNC cells. Furthermore, the EDX results highlighted increased nitrogen content on bone surfaces with these mixed clusters. Overall, the findings underscore the significant role of BMSCs in tumor growth, emphasizing the need for further exploration in potential cancer treatment strategies.

Opposing MMP-9 Expression in Mesenchymal Stromal Cells and Head and Neck Tumor Cells after Direct 2D and 3D Co-Culture.

Bone marrow-derived mesenchymal stromal cells (BMSCs) respond to a variety of tumor cell-derived signals, such as inflammatory cytokines and growth factors. As a result, the inflammatory tumor microenvironment may lead to the recruitment of BMSCs. Whether BMSCs in the tumor environment are more likely to promote tumor growth or tumor suppression is still controversial. In our experiments, direct 3D co-culture of BMSCs with tumor cells from the head and neck region (HNSCC) results in strong expression and secretion of MMP-9. The observed MMP-9 secretion mainly originates from BMSCs, leading to increased invasiveness. In addition to our in vitro data, we show in vivo data based on the chorioallantoic membrane (CAM) model. Our results demonstrate that MMP-9 induces hemorrhage and increased perfusion in BMSC/HNSCC co-culture. While we had previously outlined that MMP-9 expression and secretion originate from BMSCs, our data showed a strong downregulation of MMP-9 promoter activity in HNSCC cells upon direct contact with BMSCs using the luciferase activity assay. Interestingly, the 2D and 3D models of direct co-culture suggest different drivers for the downregulation of MMP-9 promoter activity. Whereas the 3D model depicts a BMSC-dependent downregulation, the 2D model shows cell density-dependent downregulation. In summary, our data suggest that the direct interaction of HNSCC cells and BMSCs promotes tumor progression by significantly facilitating angiogenesis via MMP-9 expression. On the other hand, data from 3D and 2D co-culture models indicate opposing regulation of the MMP-9 promoter in tumor cells once stromal cells are involved.

Treatment of extracapsular fractures of the mandibular condylar process: A retrospective evaluation of 377 cases.

BACKGROUND/AIM: Mandibular condylar fractures represent 25%-35% of all mandibular fractures. Despite profound research, there is still a controverse debate about treating these fractures conservatively or by open reduction and internal fixation (ORIF). The aim of this study is to analyse the outcome after open and closed treatment of extracapsular mandibular condyle fractures regarding general characteristics, post-treatment malocclusion, facial nerve palsy (FNP), maximum mouth opening (MMO) and parotid complications. METHODS: A retrospective cohort of 377 fractures (350 open, 27 closed treatment) was reviewed by reference to clinical and radiological pre- and postoperative documentation. Follow-up period was 12 months. Pearsons' chi-square-test, correlations, Kruskal-Wallis test and t-test were carried out for statistical analysis. RESULTS: The dominant type of fracture was type II in Spiessl and Schroll classification (50.1%). In the open treated fractures, the most common approach was retromandibular transparotid (91.7%). Post-treatment malocclusion occurred in 18.0% and was significantly increased in bilateral fractures (p = .039), in luxation fractures (p = .016) and in patients with full dentition (p = .004). After open reduction and internal fixation (ORIF), temporary FNP was documented in 7.1% whereas a permanent paresis occurred in 1.7%. FNP was significantly associated with high fractures (p = .001), comminution (p = .028) and increased duration of surgery (p = .040). Parotid complications were significantly associated with revision surgery (p = .009). Post-treatment reduction of MMO mainly occurred in female patients (p < .001) as well as in patients with bilateral fractures (p < .001), high fractures (p = .030) and concomitant mandibular (p = .001) and midfacial fractures (p = .009). CONCLUSION: Malocclusion seems to be the most frequent long-term complication after open reduction and osteosynthesis of extracapsular mandibular condyle fractures. We suggest ORIF by a transparotid approach to be an appropriate treatment with a low complication rate regarding especially FNP for extracapsular fractures of the mandibular condyle.

Buparlisib modulates PD-L1 expression in head and neck squamous cell carcinoma cell lines.

High expression of the immune checkpoint receptor PD-L1 is associated with worse patient outcome in a variety of human cancers, including head and neck squamous cell carcinoma (HNSCC). Binding of PD-L1 with its partner PD-1 generates an inhibitory signal that dampens the immune system. Immunotherapy, that is blocking the PD-1/PD-L1 checkpoint, has proven to be an effective tool in cancer therapy. However, not all patients are able to benefit from this immune checkpoint inhibition. Therefore, evidence is growing of intrinsic PD-L1 signaling in cancer cells. For example, intrinsic PD-L1 expression was associated with PI3K/Akt/mTOR signaling, which is part of diverse oncogenic processes including cell proliferation, growth and survival. In this study we demonstrate the effects of PI3K/Akt/mTOR pathway inhibition by buparlisib on PD-L1 expression in HNSCC cell lines. After buparlisib treatment for 72 h, PD-L1 was downregulated in total cell lysates of HNSCC cells. Moreover, flow cytometry revealed a downregulation of PD-L1 membrane expression. Interestingly, the buparlisib mediated effects on PD-L1 expression were reduced by additional irradiation. In PD-L1 overexpressing cells, the buparlisib induced inhibition of proliferation was neutralized. In summary, our findings imply that blocking the PI3K/Akt/mTOR pathway could be a good additional therapy for patients who show poor response to immune checkpoint therapy.

p53 inhibits the osteogenic differentiation but does not induce senescence in human dental follicle cells.

Replicative senescence causes a reduced osteogenic differentiation potential of senescent dental follicle cells (DFCs). The transcription factor p53 is often involved in the induction of cellular senescence, but little is known about its role in DFCs. This study examined for the first time the role of p53 compared to its pro-proliferative antagonist E2F-1 in terms of osteogenic differentiation potential and induction of senescence. Protein expression of E2F-1 decreased during cell aging, while p53 was expressed constitutively. Gene silencing of E2F1 (E2F-1) inhibited the proliferation rate of DFCs and increased the induction of cellular senescence. The induction of cellular senescence is regulated independently of the gene expression of TP53 (p53), since its gene expression depends on the expression of E2F1. Moreover, gene silencing of TP53 induced E2F1 gene expression and increased cell proliferation, but did not affect the rate of induction of cellular senescence. TP53 knockdown further induced the alkaline phosphatase and mineralization in DFCs. However, the simultaneous silencing of TP53 and E2F1 did not inhibit the inductive effect of TP53 knockdown on osteogenic differentiation, indicating that this effect is independent of E2F-1. In summary, our results suggest that p53 inhibits osteogenic differentiation and cell proliferation in senescent DFCs, but is not significantly involved in senescence induction.

Staging more important than grading? Evaluation of malignancy grading, depth of invasion, and resection margins in oral squamous cell carcinoma.

OBJECTIVES: The present study evaluated the predictive value of staging and grading parameters concerning the presence of lymph-node metastases, overall survival (OS), and relapse-free survival (RFS) of patients with oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: HE-stains of 135 surgically treated (R0) primary OSCCs were analyzed using a both microscopic and software-based approach. Depth of invasion (DOI) and resection margins (RM) were measured, and each case was graded according to the malignancy grading system as described by Anneroth et al. and Bryne et al. on two different sites of the tumor (surface and invasion front; TS and IF). RESULTS: Parameters that could be identified as significant predictors of OS and RFS were UICC cancer stage (p = 0.009 and p = 0.012); pT-stage as defined in the 7th edition (p = 0.029 and 0.015) and, after restaging using DOI, 8th edition (p = 0.023 and p = 0.005) of the TNM classification of malignant tumors; the presence of lymphonodular metastases (LM) (p = 0.004 and p = 0.011); degree of keratinization (p = 0.029 and p = 0.042); and pattern of growth (p = 0.029 and p = 0.024) at the TS after applying a binary scale for both parameters. Also, when directly comparing the most extreme subgroups (scores 1 and 4) of lymphoplasmacytic infiltration at the IF, there was a significant difference in OS (p = 0.046) and RFS (p = 0.005). Invasion of blood vessels (p = 0.013) and perineural invasion (p = 0.023) were significantly associated with a lower OS. Age lower than 60 years (univariate p = 0.029, multivariate p = 0.031), infiltration of lymphatic vessels (p = 0.003), infiltration of nerves (p = 0.010), pT-stage (8th edition) (p = 0.014), degree of keratinization at the IF (p = 0.033), and nuclear polymorphism at the IF (p = 0.043) after conversion to a binary scale were found to be significant prognostic parameters regarding the presence of LM. DOI evolved as a significant predictor for OS (p = 0.006), RFS (p = 0.003), and LM (p = 0.032) in metric and grouped analysis. CONCLUSIONS: The current evaluation revealed depth of invasion as strongest histologic predictor of metastatic tumor growth, overall survival, and relapse-free survival in OSCC, confirming the current adaption of the T-classification. Other distinct histologic grading parameters investigated during this study can give valuable indications of a tumor's potential aggressiveness, but the exact site, mode, and procedure need further exploration. CLINICAL RELEVANCE: Integrating measurement of DOI also into the pretherapeutic staging process could aid in treatment planning.

Lymph node ratio as a predictor for outcome in oral squamous cell carcinoma: a multicenter population-based cohort study.

OBJECTIVES: Recently, multiple studies addressed the importance of lymph node ratio (LNR) in specifying patients' risk of disease recurrence in various malignancies. The present study examines the prognostic significance of LNR in predicting outcome of oral squamous cell carcinoma (OSCC) patients after surgical treatment with curative intent. METHODS: Here, we describe a retrospective population-based cohort with 717 patients previously diagnosed with OSCC. Histopathologically verified lymph node metastasis was diagnosed in 290 patients. Among these patients, we evaluated the impact of LNR on overall survival (OAS) and recurrence-free survival (RFS) in uni- as well as multivariate analysis. RESULTS: A median cutoff (0.055) in LNR was found to significantly predict outcome in OSCC patients. Five-year OAS was 54.1% in patients with a low LNR, whereas a high LNR was associated with a 5-year OAS of 33.3% (p < 0.001). Similar results were detected for RFS with a 5-year survival rate of 49.8% (LNR low) and 30.3% (LNR high) (p = 0.002). Results were confirmed in multivariate Cox regression which substantiated the importance of LNR in predicting survival in OSCC patients. CONCLUSIONS: LNR was shown to be an independent prognostic factor for outcome of OSCC in a population-based cohort in uni- as well as multivariate analysis. Hereby, a LNR ≥ 0.055 predicted a shorter OAS and RFS in our cohort. CLINICAL RELEVANCE: Besides established histopathological factors, LNR can be used as a reliable predictor of outcome in OSCC and might therefore be further applied in evaluating adjuvant treatment after resection in curative intention.

Differential Expression of PD-L1 during Cell Cycle Progression of Head and Neck Squamous Cell Carcinoma.

The expression of PD-L1 by tumor cells is mainly associated with its immunosuppressive effect. In fact, PD-1/PD-L1 immune checkpoint inhibitors demonstrated remarkable effects in advanced cancer patients including HNSCC. In this context, irradiation is currently being investigated as a synergistic treatment modality to immunotherapy. However, the majority of HNSCC patients still show little improvement or even hyperprogression. Interestingly, there is increasing evidence for additional cell-intrinsic functions of PD-L1 in tumor cells. In previous studies, we showed that PD-L1 has a strong influence on proliferation, migration, invasion, and survival after irradiation. We demonstrated that cellular expression and localization of PD-L1 differed depending on sensitivity to irradiation. Here, we show that PD-L1 is also differentially expressed during cell cycle progression of HNSCC. Furthermore, cellular localization of PD-L1 also changes depending on a particular cell cycle phase. Moreover, distinct observations occurred depending on the general differentiation status. Overall, the function of PD-L1 cannot be generalized. Rather, it depends on the differentiation status and microenvironment. PD-L1 expression and localization are variable, depending on different factors. These findings may provide insight into why differential response to PD-1/PD-L1 antibody therapy can occur. Detailed understanding of cell-intrinsic PD-L1 functions will further allow antibody-based immunotherapy to be optimized.

Impact of Spatially Heterogeneous Trop-2 Expression on Prognosis in Oral Squamous Cell Carcinoma.

Oral cancer often presents with aggressive behavior and a high risk of recurrence and metastasis. For oral squamous cell carcinoma (OSCC), which is the most frequent histological subtype, therapy strategies include surgery, radiation therapy, chemotherapy, immune checkpoint inhibitors, and EGFR inhibitors. Recently, a Trop-2 antibody-drug conjugate (ADC) has been approved in the United States of America for the treatment of advanced triple-negative breast cancer. However, this ADC has also been tested in other solid tumors including head & neck squamous cell carcinoma. The prognostic impact of Trop-2 has already been reported for several cancers. We studied the prognostic influence of Trop-2 protein expression on OSCC patients' survival. The cohort comprised n = 229 OSCC patients with available archived tumor tissue and corresponding non-neoplastic oral mucosa tissue. Using immunohistochemistry, we investigated Trop-2 expression in both the central and peripheral regions of each tumor and in corresponding non-neoplastic oral mucosa. In patients suffering from OSCC with combined high central and low peripheral Trop-2 expression, five-year overall survival (OS) was 41.2%, whereas 55.6% of OSCC patients who presented lower central and/or higher peripheral tumoral Trop-2 expression were alive after five years (p = 0.075). In multivariate Cox regression, the expression pattern of high central tumoral and lower peripheral Trop-2 expression was significantly correlated with impaired OS (HR = 1.802, 95%-CI: 1.134-2.864; p = 0.013) and recurrence-free survival (RFS) (HR = 1.633, 95%-CI: 1.042-2.560; p = 0.033), respectively, when adjusting for co-variables. Hence, Trop-2 may serve as an independent prognostic biomarker in OSCC. In subsequent studies, the pathophysiological meaning of downregulated Trop-2 expression in the OSCC periphery has to be analyzed.

Induction of ALP and MMP9 activity facilitates invasive behavior in heterogeneous human BMSC and HNSCC 3D spheroids.

Mesenchymal stem cells (MSCs) are multipotent progenitor cells capable of differentiating into adipocytic, osteogenic, chondrogenic, and myogenic lineages. There is growing evidence that MSCs home into the tumor microenvironment attracted by a variety of signals such as chemokines, growth factors, and cytokines. Tumor-homing stem cells may originate from bone marrow-derived MSCs (BMSCs) or adipose tissue-derived MSCs. Recent scientific data suggest that MSCs in combination with tumor cells can either promote or inhibit tumorigenic behavior. In head and neck squamous cell carcinoma (HNSCC), BMSCs are reported to be enriched with a potential negative role. Here, we evaluated the effect of BMSCs from 4 different donors in combination with 4 HNSCC cell lines in a 3-dimensional multicellular spheroid model. Heterogeneous combinations revealed an up-regulation of gene and protein expression of osteogenic markers runt-related transcription factor 2 (RUNX2) and alkaline phosphatase (ALP) together with a substantial secretion of matrix metalloproteinase 9. Moreover, heterogenous BMSC/tumor spheroids showed increased invasion compared with homogenous spheroids in a Boyden chamber invasion assay. Furthermore, inhibition of ALP resulted in a substantially decreased spreading of heterogeneous spheroids on laminin-rich matrix. In summary, our data suggest a prometastatic effect of BMSCs combined with HNSCC.-Wessely, A., Waltera, A., Reichert, T. E., Stöckl, S., Grässel, S., Bauer, R. J. Induction of ALP and MMP9 activity facilitates invasive behavior in heterogeneous human BMSC and HNSCC 3D-spheroids.

Implant survival or implant success? Evaluation of implant-based prosthetic rehabilitation in head and neck cancer patients-a prospective observational study.

OBJECTIVES: Definition of implant success is unclear in prosthetic implant-based rehabilitation of head neck cancer patients. MATERIALS AND METHODS: Fifty-two patients with 309 inserted implants were included in this prospective observational study. Implant survival (in situ and loaded) and implant success (modified Albrektsson criteria) at 2-year follow-up were evaluated under the influence of patient- and implant-specific variables. RESULTS: Thirty-nine patients with 234 implants finished the study. Overall implant survival after 2 years was 92.3% (216/234) with an osseointegration rate of 94% (220/234). Implant success was 78.6% (184/234). Main reasons for failure were "bone resorption > 1.7mm" (n = 27, 11.5%) and "implant not in situ or not loaded" (n = 18, 7.7%). Smoking (OR 3.1, p = 0.034), bone grafts (OR 2.4, p = 0.021) and radiation dose > 60 Gy (OR 3.8, p = 0.025) revealed as significant predictors for implant failure. CONCLUSION: Implant survival differs significantly from implant success in head and neck cancer patients. Implant success is mainly determined by radiographic peri-implant bone resorption. CLINICAL RELEVANCE: Dealing with head and neck cancer patients a higher amount of peri-implant bone resorption must be taken into account and warrants for intensified implant monitoring.

A prospective clinical pilot study on the effects of a hydrogen peroxide mouthrinse on the intraoral viral load of SARS-CoV-2.

OBJECTIVES: SARS-CoV-2 is mainly transmitted by inhalation of droplets and aerosols. This puts healthcare professionals from specialties with close patient contact at high risk of nosocomial infections with SARS-CoV-2. In this context, preprocedural mouthrinses with hydrogen peroxide have been recommended before conducting intraoral procedures. Therefore, the aim of this study was to investigate the effects of a 1% hydrogen peroxide mouthrinse on reducing the intraoral SARS-CoV-2 load. METHODS: Twelve out of 98 initially screened hospitalized SARS-CoV-2-positive patients were included in this study. Intraoral viral load was determined by RT-PCR at baseline, whereupon patients had to gargle mouth and throat with 20 mL of 1% hydrogen peroxide for 30 s. After 30 min, a second examination of intraoral viral load was performed by RT-PCR. Furthermore, virus culture was performed for specimens exhibiting viral load of at least 103 RNA copies/mL at baseline. RESULTS: Ten out of the 12 initially included SARS-CoV-2-positive patients completed the study. The hydrogen peroxide mouthrinse led to no significant reduction of intraoral viral load. Replicating virus could only be determined from one baseline specimen. CONCLUSION: A 1% hydrogen peroxide mouthrinse does not reduce the intraoral viral load in SARS-CoV-2-positive subjects. However, virus culture did not yield any indication on the effects of the mouthrinse on the infectivity of the detected RNA copies. CLINICAL RELEVANCE: The recommendation of a preprocedural mouthrinse with hydrogen peroxide before intraoral procedures is questionable and thus should not be supported any longer, but strict infection prevention regimens are of paramount importance. TRIAL REGISTRATION: German Clinical Trials Register (ref. DRKS00022484).

WNT5A supports viability of senescent human dental follicle cells.

The osteogenic differentiation of dental follicle cells (DFCs) is inhibited by the onset of cellular senescence, but the cause for this is largely unknown. Recently it was shown that WNT5a, which is an inductor of the non-canonical WNT pathway, stimulates both cellular senescence and osteogenic differentiation of different cell types. In this study, we investigated the role of WNT5a for viability and osteogenic differentiation in human DFCs after the induction of cellular senescence. DFCs were cultivated until the induction of cellular senescence. The induction of cellular senescence was confirmed by ß-galactosidase staining, estimation of population doubling time, and slightly telomere length shortening. After induction of cellular senescence, the expression of WNT5A and the potential to induce the osteogenic differentiation decreased. Inhibition of WNT5A by specific siRNAs had significant effect on the viability of DFCs. Cell proliferation was reduced, whereas both cellular senescence and cell death were increased in DFCs. However, an inhibition of WNT5A did only slightly effect the osteogenic differentiation of DFCs. Our results suggest that WNT5A supports viability during both cell proliferation and osteogenic differentiation of DFCs.

Influence of early elective tracheostomy on the incidence of postoperative complications in patients undergoing head and neck surgery.

BACKGROUND: The incidence of postoperative complications after head and neck surgery is high. This study evaluated the influence of early elective tracheostomy on the incidence of postoperative pneumonia and delirium. METHODS: We reviewed the data of all patients who had undergone removal of an oropharyngeal tumor and microsurgical tissue transfer at our department in a two year period. Pearson's Chi-squared test and the Fischer's exact t-test were then used to measure the influence of patients' preexisting conditions and risk factors and of early elective tracheostomy on the incidence of postoperative complications. RESULTS: In total, 47 cases were analyzed. Patients with an endotracheal tube were ventilated for a longer time (3.4 days vs. 1.5 days) and were transferred to the regular ward later (after 6.9 days vs. 4.7 days) than patients with tracheostomy. Only 1 (2.1%) of the patients with a tracheostomy developed pneumonia in contrast to 5 intubated patients (10.6%) and only 2 patients with a tracheostomy developed postoperative delirium (9.5%) in contrast to 8 intubated patients (30.8%). CONCLUSION: Early primary tracheostomy in patients undergoing resection of oropharyngeal cancer seems to have numerous benefits, such as lower complication rates with regard to pneumonia and postoperative delirium and shorter duration of both mechanical ventilation and intensive care unit (ICU) stays. Further studies have to evaluate if these benefits also influence morbidity and mortality rates.

Predictive value of FHIT, p27, and pERK1/ERK2 in salivary gland carcinomas: a retrospective study.

OBJECTIVES: The aim of this study was to investigate the predictive value of the biomarkers FHIT, p27, and pERK1/ERK2 in salivary gland carcinomas. MATERIAL AND METHODS: Immunohistochemical staining of FHIT, p27, and pERK1/ERK2 of 265 patients with salivary gland carcinomas was conducted, and associations with clinico-histopathological data, overall survival, and disease-specific survival were examined. RESULTS: Expression of FHIT (quick score 98.7 vs. 206.4) and p27 (QS 187.3 vs. 244.8) was significantly lower in carcinomas compared to non-tumor control tissue. Loss of FHIT frequently occurred in ACC (55.2%), SDC (68.2%), and SCC (100%). In the totality of tumors, loss of FHIT expression was found in 46.7% (106/227) and was significantly associated with advanced T stage and UICC stage, high-grade histology, loss of p27, PI3K, and survivin. FHIT positivity went along with significantly better overall and disease-specific survival. Negativity of p27 occurred in 28.7% (70/244) of tumors, particularly in SDC (54.4%) and SCC (50%). In the totality of tumors, p27 was associated with advanced patient age, high-grade histology, PI3K, survivin as well as better overall and disease-specific survival (p < 0.05). Positive pERK1/ERK2 expression correlated with positive survivin expression but did not affect overall survival in the totality of tumors. In mucoepidermoid carcinomas, pERK1/ERK2 expression was associated with low-grade malignancy, positive nuclear survivin, and better disease-specific survival. CONCLUSIONS: Loss of FHIT and p27 characterizes aggressive tumor growth and unfavorable prognosis in salivary gland cancer. CLINICAL RELEVANCE: The results may help to stratify patient-specific therapies according to individual tumor characteristics.

Challenges in Exosome Isolation and Analysis in Health and Disease.

A growing body of evidence emphasizes the important role exosomes in different physiological and pathological conditions. Exosomes, virus-size extracellular vesicles (EVs), carry a complex molecular cargo, which is actively processed in the endocytic compartment of parental cells. Exosomes carry and deliver this cargo to recipient cells, serving as an intercellular communication system. The methods for recovery of exosomes from supernatants of cell lines or body fluids are not uniformly established. Yet, studies of the quality and quantity of exosome cargos underlie the concept of "liquid biopsy." Exosomes are emerging as a potentially useful diagnostic tool and a predictor of disease progression, response to therapy and overall survival. Although many novel approaches to exosome isolation and analysis of their cargos have been introduced, the role of exosomes as diagnostic or prognostic biomarkers of disease remains unconfirmed. This review considers existing challenges to exosome validation as disease biomarkers. Focusing on advantages and limitations of methods for exosome isolation and characterization, approaches are proposed to facilitate further progress in the development of exosomes as biomarkers in human disease.