Head And Neck Squamous Cell Carcinoma Carcinogenesis Research Articles

Down-regulation of the tumor suppressor miR-34a contributes to head and neck cancer by up-regulating the MET oncogene and modulating tumor immune evasion

BackgroundMicroRNAs (miRs) have been shown to play an important role in tumorigenesis, including in head and neck squamous cell carcinoma (HNSCC). The miR-34 family is thought to play a role in tumor suppression, but the exact mechanism of their action in HNSCC is not well understood. Moreover, the impact of chromosomal changes and mutation status on miR-34a expression remains unknown.MethodsDifferential expression of miR-34a, MET, and genomic alterations were assessed in the Cancer Genome Atlas (TCGA) datasets as well as in primary HNSCC and adjacent normal tissue. The biological functions of miR-34a in HNSCC were investigated in samples derived from primary human tumors and HNSCC cell lines. The expression of MET was evaluated using immunohistochemistry, and the molecular interaction of miR-34a and MET were demonstrated by RNA pulldown, RNA immunoprecipitation, luciferase reporter assay, and rescue experiments. Lastly, locked nucleic acid (LNA) miRs in mouse xenograft models were used to evaluate the clinical relevance of miR-34a in HNSCC tumor growth and modulation of the tumor microenvironment in vivo.ResultsChromosome arm 1p loss and P53 mutations are both associated with lower levels of miR-34a. In HNSCC, miR-34a acts as a tumor suppressor and physically interacts with and functionally targets the proto-oncogene MET. Our studies found that miR-34a suppresses HNSCC carcinogenesis, at least in part, by downregulating MET, consequently inhibiting HNSCC proliferation. Consistent with these findings, administration of LNA-miR-34a in an in vivo model of HNSCC leads to diminished HNSCC cell proliferation and tumor burden in vitro and in vivo, represses expression of genes involved in epithelial-mesenchymal transition, and negates the oncogenic effect of MET in mouse tumors. Consistently, LNA-miR-34a induced a decreased number of immunosuppressive PDL1-expressing tumor-associated macrophages in the tumor microenvironment. In HNSCC patient samples, higher levels of miR-34a are significantly associated with a higher frequency of Th1 cells and CD8 naïve T cells.ConclusionsOur results demonstrate that miR-34a directly targets MET and maintains anti-tumor immune activity. We propose miR-34a as a potential new therapeutic approach for HNSCC.

Human papillomavirus and head and neck squamous cell carcinoma in a UK population

Human papillomavirus (HPV) is an evolving important risk factor for head and neck cancer (HNC), especially for individuals who do not smoke and drink alcohol. The aim of this study was to establish the prevalence of HPV infection and elucidate its association with head and neck squamous cell carcinoma (HNSCC) patients in UK population. The presence and association of HPV was investigated in HNSCC patients in this retrospective clinical study. Samples were obtained from archived biopsies and resections. HPV screening was performed by the use of polymerase chain reaction (PCR) using the GP5+/GP6+ and the SPF1/2 consensus as primers and by immunohistochemistry (IHC). Samples of viral warts that were IHC positive for HPV and fibroepethelial polyps (FEP) were used, as positive and negative controls, respectively. The cohort included 124 patients with HNSCC with an age range of 27-97 years (median, 60 years) and a male to female ratio of 2:1. Among the 124 HNSCC, 43/124 (34.7%) were from the tongue, 74/124 (60%) presented with advanced stage III or IV disease, 112/124 (90%) had a conventional phenotype, 84/124 (68%) were moderately differentiated, and 89/124 (72%) had bands or cords at the invasive front. Of the 124 patients with HNSCC, 84/124 (68%) demonstrated the presence of HPV, 0/124 (0%) was for oral squamous cell carcinomas (OSCC). HPV16 was the associated virus type in all positive samples. However, no significant association was observed between HPV positivity and other clinico-pathological variables including age and gender of the patients, stage, and malignancy differentiation. The results we provide suggest that HPV infection is low in HNSCC, in general, and absent in OSCC, specifically, in this UK population during this time period. This implies that HPV infection may not play an important role in HNSCC carcinogenesis compared to other risk factors in UK population. This information can aid in more effective treatment approaches for treating UK cases of HNSCC.

Complex Interaction Among Immune, Inflammatory, and Carcinogenic Mechanisms in the Head and Neck Squamous Cell Carcinoma.

Inflammation is deeply involved in the development of most types of cancer. Many studies focus on the interaction between immune-inflammatory mechanisms and tumorigenesis in the head and neck squamous cell carcinoma (HNSCC). In this chapter, we emphasize the complexity of processes underlying this interaction and discuss the mechanisms of carcinogenesis in HNSCC with a special focus on metabolic changes, inflammation, and the immune landscape. Unveiling complex connections between immuno-inflammatory processes and tumor initiation, promotion, and progression will open new directions in the reliable identification of predictive factors and therapeutic targets in HNSCC.

Effect of Hypoxia on Proliferation and the Expression of the Genes HIF-1α and JMJD1A in Head and Neck Squamous Cell Carcinoma Cell Lines.

The aim of the study was to investigate the effects of hypoxia on proliferation and the expression of HIF-1α (hypoxia-inducible factor 1 alpha) and JMJD1A (jumonji domain 1A) in head and neck squamous cell carcinoma (HNSCC). FaDu and HLaC78 cells were incubated for 1-24 h in hypoxia and normoxia. Cell proliferation, mRNA and protein levels of HIF-1α and JMJD1A were quantified by counting, PCR and western blot. Hypoxia led to a constant decrease in cell proliferation. Short hypoxia resulted in an increase in HIF-1α mRNA levels. This effect was reversed after longer incubation. The western blot for HIF-1α showed a maximum accumulation after 3-6 h of hypoxia. In FaDu cells, the concentration of JMJD1A reached a peak after 6 h and decreased thereafter, whereas in HLaC78 cells, it presented a second peak after 48 h. The transcription factors HIF-1α and JMJDA1 were confirmed as relevant hypoxia-dependent regulators of carcinogenesis in HNSCC.

Cigarette smoking promotes keratinocyte malignancy via generation of cancer stem-like cells.

Objectives: Cigarette smoking is involved in the pathogenesis of head and neck squamous cell carcinoma (HNSCC). However, the underlying molecular mechanisms of cigarette smoking-induced HNSCC carcinogenesis are unclear and may involve cancer stem-like cell generation. We examined the effects of cigarette smoke condensate (CSC) on the formation of cancer stem-like cells, which are rich in octamer-binding transcription factor (OCT)-4, inhibitor of differentiation 1 (ID1), nuclear factor (NF)-κB, and B lymphoma Mo-MLV insertion region 1 homolog (BMI-1).Materials and Methods: We used in vitro, in vivo, and archival human HNSCC tissue analysis to evaluate the effects of CSC on cancer stem-like cell formation.Results: We found that CSC regulated OCT-4 expression, which subsequently regulated ID1 and NF-κB, at the promoter, mRNA, and protein levels in vitro. Furthermore, OCT-4 knockdown with siRNA reduced ID1 expression. ID1 and NF-κB synergistically increased the expression of BMI-1 and stimulated keratinocyte sphere generation. In vivo, ID1 and NF-κB acted together to generate malignant xenograft tumors, which were aggressive locally and systemically metastatic. Clinical data confirmed that ID1- and NF-κB-positive patients had poor clinical outcomes and 5-year disease-free survival.Conclusion: Our data suggest that smoking cigarettes promoted cancer stem-like cell generation in the head and neck area via the OCT-4/ID1/NF-κB/BMI-1 signaling pathway.

The head and neck cancer genome in the era of immunotherapy.

The recent success of immunotherapy in head and neck squamous cell carcinoma (HNSCC) has necessitated a new perspective on the cancer genome. Here we review recent advances in the carcinogenesis and molecular genetics of HNSCC with an eye on their implications for cancer immunity. Newer sequencing technologies have recently facilitated dissection of the complex interaction between the HPV virus, tumor, host factors, and the tumor microenvironment (TME) that help shed light on how the immune system interacts with head and neck malignancies.

Targeting methyltransferase PRMT5 retards the carcinogenesis and metastasis of HNSCC via epigenetically inhibiting Twist1 transcription

Protein arginine methyltransferase 5 (PRMT5) is an important type II arginine methyltransferase that can play roles in cancers in a highly tissue-specific manner, but its role in the carcinogenesis and metastasis of head and neck squamous cell carcinoma (HNSCC) remains unclear. Here, we detected PRMT5 expression in HNSCC tissues and performed series of in vivo and in vitro assays to investigate the function and mechanism of PRMT5 in HNSCC. We found that PRMT5 was overexpressed in dysplastic and cancer tissues, and associated with lymph node metastasis and worse patient survival. PRMT5 knockdown repressed the malignant phenotype of HNSCC cells in vitro and in vivo. PRMT5 specific inhibitor blocked the formation of precancerous lesion and HNSCC in 4NQO-induced tongue carcinogenesis model, prevented lymph node metastasis in tongue orthotopic xenograft model and inhibited cancer development in subcutaneous xenograft model and Patient-Derived tumor Xenograft (PDX) model. Mechanistically, PRMT5-catalyzed H3R2me2s promotes the enrichment of H3K4me3 in the Twist1 promoter region by recruiting WDR5, and subsequently activates the transcription of Twist1. The rescue experiments indicated that overexpressed Twist1 abrogated the inhibition of cell invasion induced by PRMT5 inhibitor. In summary, this study elucidates that PRMT5 inhibition could reduce H3K4me3-mediated Twist1 transcription and retard the carcinogenesis and metastasis of HNSCC.

Insight toward the MicroRNA Profiling of Laryngeal Cancers: Biological Role and Clinical Impact.

Head and neck squamous cell carcinoma (HNSCC), a heterogeneous disease arising from various anatomical locations including the larynx, is a leading cause of death worldwide. Despite advances in multimodality treatment, the overall survival rate of the disease is still largely dismal. Early and accurate diagnosis of HNSCC is urgently demanded in order to prevent cancer progression and to improve the quality of the patient’s life. Recently, microRNAs (miRNAs), a family of small non-coding RNAs, have been widely reported as new robust tools for prediction, diagnosis, prognosis, and therapeutic approaches of human diseases. Abnormally expressed miRNAs are strongly associated with cancer development, resistance to chemo-/radiotherapy, and metastatic potential through targeting a large variety of genes. In this review, we summarize on the recent reports that emphasize the pivotal biological roles of miRNAs in regulating carcinogenesis of HNSCC, particularly laryngeal cancer. In more detail, we report the characterized miRNAs with an evident either oncogenic or tumor suppressive role in the cancers. In addition, we also focus on the correlation between miRNA deregulation and clinical relevance in cancer patients. On the basis of intriguing findings, the study of miRNAs will provide a new great opportunity to access better clinical management of the malignancies.

The Importance of Cancer-Associated Fibroblasts in the Pathogenesis of Head and Neck Cancers.

Despite progress in anticancer therapies, head and neck squamous cell carcinoma (HNSCC) has still a low survival rate. Recent studies have shown that tumour stroma may play an important role in the pathogenesis of this malignant disease. Fibroblasts are a major component of the tumour microenvironment and may significantly influence HNSCC progression as indicated by the contribution they make to important hallmarks of cancer, such as inflammation, non-restricted growth, angiogenesis, invasion, metastasis, and therapy resistance. It is well known that tumour cells can confer a cancer-associated fibroblast (CAF) phenotype that supports the growth and dissemination of cancer cells. CAFs can stimulate cancer progression through cell-cell contacts and communication, remodelling of extracellular matrix, and production of many signal molecules and matrix metalloproteinases. Consequently, genetic changes in epithelial cells are probably not the only factor that drives HNSCC carcinogenesis. Non-genetic changes in the tumour stroma can also be significantly involved. Stress-induced signals can induce a multicellular program, creating a field of tissue that is predisposed to malignant transformation. The “field cancerization” concept represents a process of active evolution of intercellular interactions and feedback loops between tumour and stromal cells. This model paves the way to study cancer from a new perspective and identify new therapeutic targets. In this review, we discuss current knowledge about CAFs, such as their cellular origin, phenotypical plasticity and functional heterogeneity, and stress their contribution to HNSCC progression. This article was supported by the project AZV 16-29835A. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 18. 6. 2019 Accepted: 9. 9. 2019.

Integrated analysis of DNA methylation and mRNA expression profiles to identify key genes in head and neck squamous cell carcinoma.

DNA methylation has been demonstrated to play significant roles in the etiology and pathogenesis of head and neck squamous cell carcinoma (HNSCC). In the present study, methylation microarray dataset (GSE87053) and gene expression microarray dataset (GSE23558) were downloaded from GEO database and analyzed through R language. A total of 255 hypermethylated-downregulated genes and 114 hypomethylated-upregulated genes were finally identified. Functional enrichment analyses were performed and a comprehensive protein–protein interaction (PPI) network was constructed. Subsequently, the top ten hub genes selected by Cytoscape software were subjected to further analyses. It was illustrated that the expression level of CSF2, CTLA4, ETS1, PIK3CD, and CFTR was intimately associated with HNSCC. Survival analysis suggested that CTLA4 and FGFR2 could serve as effective independent prognostic biomarkers for HNSCC patients. Overall, our study lay a groundwork for further investigation into the underlying molecular mechanisms in HNSCC carcinogenesis, providing potential biomarkers and therapeutic targets for HNSCC.

SMAD4 Somatic Mutations in Head and Neck Carcinoma Are Associated With Tumor Progression.

As the incidence and the mortality rate of head and neck squamous cell carcinoma (HNSCC) is increasing worldwide, gaining knowledge about the genomic changes which happen in the carcinogenesis of HNSCC is essential for the diagnosis and therapy of the disease. SMAD4 (DPC4) is a tumor suppressor gene. It is located at chromosome 18q21.1 and a member of the SMAD family. Which mediates the TGF-β signaling pathway, thereby controlling the growth of epithelial cells. In the study presented here, we analyzed tumor samples by multiplex PCR-based next-generation sequencing (NGS) and found deleterious mutations of SMAD4 in 4.1% of the tumors. Knock-down experiments of endogenous and exogenous SMAD4 expression demonstrated that SMAD4 is involved in the migration and invasion of HNSCC cells. Functional analysis of a missense mutation in the MH1 domain of SMAD4 may be responsible for the loss of function in suppressing tumor progression. Missense SMAD4 mutations, therefore, could be useful prognostic determinants for patients affected by HNSCCs. This report is the first study where NGS analysis based on multiplex-PCR is used to demonstrate the imminent occurrence of missense SMAD4 mutations in HNSCC cells. The gene analysis that we performed may support the identification of SMAD4 mutations as a diagnostic marker or even as a potential therapeutic target in head and neck cancer. Moreover, the analytic strategy proposed for the detection of mutations in the SMAD4 gene may be validated as a platform to assist mutation screening.

High P4HA1 expression is an independent prognostic factor for poor overall survival and recurrent-free survival in head and neck squamous cell carcinoma.

BackgroundProlyl 4‐hydroxylase subunit alpha 1 (P4HA1) plays a critical role in modulating the extracellular matrix and promoting tumor progression in various cancers. However, the association between P4HA1 and head and neck squamous cell carcinomas (HNSCC) has not been thoroughly elucidated to date.Methods P4HA1 mRNA and protein expression in cancer and normal tissues were analyzed using The Cancer Genome Atlas (TCGA), Gene Expression Omnibus, and Human Protein Atlas databases. Quantitative PCR was applied to determine P4HA1 mRNA expression levels in 162 paired HNSCC and adjacent normal tissues. The cBioPortal for Cancer Genomics was utilized to explore P4HA1 genetic alterations in HNSCC. Then, KEGG analysis of P4HA1 co‐expressed genes in HNSCC was conducted using ClueGo in Cytoscape.Results P4HA1 mRNA and protein levels were significantly increased in HNSCC tissues compared with normal tissues. High P4HA1 expression in HNSCC tissues was significantly associated with tumor category, lymphatic metastasis and pathological stage. The area under summary receiver operating characteristic curve of TCGA and validation cohort was 0.887 and 0.883, respectively. Moreover, elevated P4HA1 expression was associated with unfavorable OS (HR: 1.728, P = .001) and RFS (HR: 2.025, P = .002) in HNSCC patients.ConclusionsThis integrated analysis provides strong evidence that increasing P4HA1 expression is significantly associated with the carcinogenesis of HNSCC. Additionally, high P4HA1 expression serves as both diagnostic biomarker and independent prognostic factor for poor OS and RFS in HNSCC patients.

HPV-negative and HPV-positive HNSCC cell lines show similar numerical but different structural chromosomal aberrations.

It was tested whether the difference in carcinogenesis between noxa and human papillomavirus (HPV)-driven head and neck squamous cell carcinoma (HNSCC) is associated with a variation in genomic instability. Conventional and molecular cytogenetics in HPV-positive and HPV-negative HNSCC cell lines. Numerical aneuploidy determined by multicolor fluorescence in situ hybridization and DNA ploidy was very similar for both entities with most chromosomes being present either in quadruplicate or triplicate, and only few are still diploid with, however, a striking similarity in the overall pattern. A clear difference was seen concerning the translocations formed, with no difference in the total amount but with a significantly higher genomic instability of HPV-positive cell lines at chromosome 3 as compared to HPV-negative cells. The different processes of carcinogenesis of HPV-positive and HPV-negative HNSCC appear to result in a similar pattern of numerical but a clear difference in structural chromosomal aberrations.

WNT/Β-CATENIN SIGNALING PATHWAY REGULATES TUMOR-INITIATING CELLS IN HEAD AND NECK SQUAMOUS CELL CARCINOMA

Objectives Head and neck squamous cell carcinoma (HNSCC) is one of the leading cancers, with a 40% 5-year survival rate in advanced cases. HNSCC is notorious for its high recurrence rate and frequent occurrence of synchronous/metachronous primary tumors. Tumor initiating cells (TICs) model was proposed to explain its tumor heterogeneity and frequent recurrences. Lineage tracing is a genetic approach that allows identification of TICs in their native habitats and characterization of their in vivo behavior. Findings Our re-analysis of TCGA data revealed that high expression of AXIN2, a downstream target of Wnt signaling, was significantly correlated with low survival rate of HNSCC. To characterize the Wnt-responsive cell population, we established a carcinogen-induced model using Axin2-CreER reporter mice. After tamoxifen induction, clonal expansion of fluorescent reporter-positive cells (Wnt-responsive tumor cells) was visualized in the basal cell layer of epithelial dysplasia and HNSCC, suggesting the critical role of Wnt in regulating TICs in early stages of carcinogenesis. β-catenin and LEF1 immunofluorescent staining were performed to confirm Wnt activation. Lineage tracing was also accomplished in 3D organoid culture. The fluorescent reporter-positive cells were capable of forming organoids. Furthermore, application of cisplatin enriched AIXN2 cell population. Conclusions Activation of Wnt/β-catenin signaling pathway is an early event in HNSCC carcinogenesis. Lineage tracing using the Axin2-CreER reporter may link TICs properties with a fundamental signaling pathway in normal development. Further research is required to clarify the role of Wnt-responsive TICs in recurrence and therapy resistance of HNSCC.

4E-BP1 Is a Tumor Suppressor Protein Reactivated by mTOR Inhibition in Head and Neck Cancer.

Aberrant activation of the PI3K-mTOR signaling pathway occurs in >80% of head and neck squamous cell carcinomas (HNSCC), and overreliance on this signaling circuit may in turn represent a cancer-specific vulnerability that can be exploited therapeutically. mTOR inhibitors (mTORi) promote tumor regression in genetically defined and chemically induced HNSCC animal models, and encouraging results have been recently reported. However, the mTOR-regulated targets contributing to the clinical response have not yet been identified. Here, we focused on EIF4E-BP1 (4E-BP1), a direct target of mTOR that serves as key effector for protein synthesis. A systematic analysis of genomic alterations in the PIK3CA-mTOR pathway in HNSCC revealed that 4E-BP1 is rarely mutated, but at least one 4E-BP1 gene copy is lost in over 35% of the patients with HNSCC, correlating with decreased 4E-BP1 protein expression. 4E-BP1 gene copy number loss correlated with poor disease-free and overall survival. Aligned with a tumor-suppressive role, 4e-bp1/2 knockout mice formed larger and more lesions in models of HNSCC carcinogenesis. mTORi treatment or conditional expression of a mutant 4E-BP1 that cannot be phosphorylated by mTOR was sufficient to disrupt the translation-initiation complex and prevent tumor growth. Furthermore, CRISPR/Cas9-targeted 4E-BP1 HNSCC cells resulted in reduced sensitivity to mTORi in vitro and in vivo. Overall, these findings indicate that in HNSCC, mTOR persistently restrains 4E-BP1 via phosphorylation and that mTORi can restore the tumor-suppressive function of 4E-BP1. Our findings also support 4E-BP1 expression and phosphorylation status as a mechanistic biomarker of mTORi sensitivity in patients with HNSCC. SIGNIFICANCE: These findings suggest that EIF4E-BP1 acts as a tumor suppressor in HNSCC and that 4E-BP1 dephosphorylation mediates the therapeutic response to mTORi, providing a mechanistic biomarker for future precision oncology trials.

Detection of human papillomavirus in cases of head and neck squamous cell carcinoma by RNA-seq and VirTect.

Next‐generation sequencing provides an opportunity to detect viral species from RNA‐seq data of human tissues, but existing computational approaches do not perform optimally on clinical samples. We developed a bioinformatic method called VirTect for detecting viruses in neoplastic human tissues using RNA‐seq data. Here, we used VirTect to analyze RNA‐seq data from 363 head and neck squamous cell carcinoma (HNSCC) patients and identified 22 human papillomavirus (HPV)‐induced HNSCCs. These predictions were validated by manual review of pathology reports on histopathologic specimens. VirTect showed better performance in recall and accuracy compared to the two existing prediction methods, VirusFinder and VirusSeq, in identifying viral sequences from RNA‐seq data. The majority of HPV carcinogenesis studies thus far have been performed on cervical cancer and generalized to HNSCC. Our results suggest that carcinogenesis of HPV‐induced HNSCC and other cases of HNSCC involve different genes, so understanding the underlying molecular mechanisms will have a significant impact on therapeutic approaches and outcomes. In summary, RNA‐seq together with VirTect can be an effective solution for the detection of viruses from tumor samples and can facilitate the clinicopathologic characterization of various types of cancers with broad applications for oncology.

Identification of novel methylated DNA marker ZNF569 for head and neck squamous cell carcinoma.

Aberrant DNA methylation pattern plays an indispensable role in the initiation and development of head and neck squamous cell carcinoma (HNSCC). It is well recognized that lymph node metastasis is closely with unfavorable prognosis of HNSCC. Therefore, exploring the methylation events accounting for the lymph node metastasis of HNSCC is very important for improving the clinical outcome of HNSCC. Methylation data, RNA-seq data and clinical data were downloaded from The Cancer Genome Atlas (TCGA) and processed using the R package TCGA-Assembler. MethylMix was use for data analysis by integrating both methylation and gene expression data on HNSCC patients with lymph node metastasis and without lymph node metastasis. Pathway analysis was performed on significantly altered genes using ConsensusPathDB. The role of our interested gene zinc figure protein 569 (ZNF569) in HNSCC was further evaluated. Our results identified many novel hypermethylated/hypomethylated genes that might be closely associated with the lymph node metastasis of HNSCC. Pathway analysis revealed that increase in methylation of genes involved in generic transcription pathway including zinc figure proteins. ZNF569 was hypermethylated in HNSCC tissues especially those with lymph node metastasis. In addition, the expression levels of ZNF569 mRNA and protein were significantly lower in HNSCC tissues and cell lines compared to their respective controls. Moreover, overexpression of ZNF569 inhibited the proliferation, migration and invasion of HNSCC cells. HNSCC patients with lower ZNF569 expression suffered a significantly shorter overall survival than those with higher ZNF569 expression. In conclusion, we have identified many novel differentially methylated genes that might be important for the lymph node metastasis of HNSCC. In addition, ZNF569 might play a tumor suppressive role in carcinogenesis of HNSCC.

Gene Expression Comparison Between the Primary Tumor and its Lymph Node Metastasis in Head and Neck Squamous Cell Carcinoma: A Pilot Study.

In metastatic head and neck squamous cell carcinoma (HNSCC) the metastatic tumor does not always keep the same gene expression profile as the parental tumor, which may influence the course of the disease. The aim of this study was to compare the expression of genes implicated in HNSCC carcinogenesis between the primary tumor and the corresponding lymph node metastasis. Eighteen HNSCC, their corresponding node metastases and non-neoplastic tissues were studied by RT-qPCR for the expression of EGFR, VEGF, claudin7, maspin, survivin and SCCA. The levels of expression were correlated with histological characteristics and patients' prognosis. All genes except for survivin displayed different expression in node metastasis compared to the primary tumor. The expression of EGFR, survivin, maspin, and claudin7 in node metastasis and SSCA in the primary tumor affected the prognosis. SCCA expression is associated with the expression of claudin7 and maspin. P16-positive tumors expressed low levels of VEGF and SCCA, while keratinizing tumors over-expressed VEGF. Differential gene expression levels in node metastases compared to the primary tumor is linked to the prognosis of HNSCC patients. The histological/immunohisto-chemical characteristics of the tumor are associated with these genes expression changes.

Deletion of C9orf53 promotes the growth of head and neck squamous cell carcinoma and is associated with poor prognosis of patients with head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is the fifth most common carcinoma worldwide, and accounts for ~600,000 new cases every year. The information on the molecular carcinogenesis of HNSCC is very limited. In the present study, the role of C9orf53 in HNSCC was investigated. The levels of C9orf53 were assayed by reverse transcription-quantitative polymerase chain reaction. The levels of C9orf53 in cells were overexpressed by overexpression plasmid and inhibited by small-interfering RNA. Cell proliferation was assayed by MTT, and cell apoptosis was assessed by FACS analysis. It was demonstrated that C9orf53 deletion was associated with a decreased survival of patients. The level of C9orf53 in HNSCC tissues was lower compared with the matched normal tissues adjacent to tumors. A lower expression of C9orf53 promoted cell proliferation, and the overexpression of C9orf53 induced cell apoptosis. In conclusion, a low level of C9orf53 in HNSCC promoted the growth of HNSCC cells, which might be associated with the low survival rate of patients with HNSCC.

Transforming growth factor-β signaling in head and neck squamous cell carcinoma: Insights into cellular responses.

Head and neck squamous cell carcinoma (HNSCC) arises in the oral cavity, salivary glands, larynx, pharynx, nasal cavity and paranasal sinuses, and is characterized by high morbidity and metastasis rates. Transforming growth factor-β (TGF-β) is a homodimeric protein known to be a multifunctional regulator in target cells and to serve a pivotal role in numerous types of cancer, including HNSCC. The role of TGF-β signaling in carcinogenesis can change from tumor-suppressing to tumor-promoting. In addition, TGF-β induces epithelial-mesenchymal transition and restrains immune surveillance on malignant cells. In the present review, the effects of TGF-β signaling at a cellular level were discussed, which includes the regulation of tumor cells, immune cells and other stromal cells, as well as the possible mechanisms underlying the conversion from a tumor suppressor to a tumor promoter in HNSCC. Further research is required to improve the understanding on how this network is involved in carcinogenesis, progression and metastases in HNSCC.