Angiogenesis in nasopharyngeal carcinoma: insights, imaging, and therapeutic strategies

Nasopharyngeal carcinoma (NPC) is a highly prevalent head and neck malignancy in southern China frequently diagnosed at advanced stages owing to subtle early symptoms and associated metastasis. Angiogenesis emerges as a pivotal factor in NPC progression, with numerous angiogenesis-related factors showing aberrant expression and contributing to increased neovascularization within NPC tumors. These abnormal vessels not only nourish tumor growth but also facilitate metastasis, culminating in unfavorable patient outcomes. Multiple studies have demonstrated the applicability of various imaging techniques for assessing angiogenesis in NPC tumors, thus serving as a foundation for personalized treatment strategies and prognostic assessments. Anti-angiogenic therapies have exhibited significant potential for inhibiting NPC angiogenesis and exerting anti-tumor effects. To enhance efficacy, anti-angiogenic drugs are frequently combined with other treatment modalities to synergistically enhance anti-tumor effects while mitigating the side effects associated with single-agent therapies, consequently improving patient prognosis. Identifying the potential mechanisms and key targets underlying NPC angiogenesis and exploring more effective detection and treatment approaches holds promise for shaping the future of NPC diagnosis, treatment, and prognosis, thereby offering new avenues and perspectives for research and clinical practice.

The four‑microRNA signature identified by bioinformatics analysis predicts the prognosis of nasopharyngeal carcinoma patients

The aim of the present study was to identify microRNAs (miRNAs) that predict the prognosis of patients with nasopharyngeal carcinoma by integrated bioinformatics analysis. First, the original microarray dataset GSE32960, including 312 nasopharyngeal carcinomas and 18 normal samples, was downloaded from the Gene Expression Omnibus database. In addition, 46 differentially expressed miRNAs (DEMs) were screened. Then, four miRNAs, including hsa-miR-142-3p, hsa-miR-150, hsa-miR-29b, and hsa-miR-29c, were obtained as prognostic markers by combining univariate Cox regression analysis with weighted gene coexpression network analysis (WGCNA). Subsequently, the risk score of 312 NPC patients from the signature of miRNAs was calculated, and patients were divided into high-risk or low-risk groups. Notably, compared with patients with low-risk scores, high-risk groups had shorter disease-free survival (DFS), overall survival (OS), and distant metastasis-free survival (DMFS). Receiver operating characteristic curve (ROC) analysis indicated that the risk score was a very effective prognostic factor. Moreover, the Search Tool for the Database for Annotation, Visualization, and Integrated Discovery (DAVID), Cytoscape, starBase, and Retrieval of Interacting Genes database (STRING) were used to establish the miRNA-mRNA correlation network and the protein-protein interaction (PPI) network. In addition, the shared genes superimposing 888 protein-coding genes targeted by four hub miRNAs and 1,601 upregulated differentially expressed mRNAs accounted for 127 and were used for subsequent gene functional enrichment analysis. In particular, biological pathway analysis indicated that these genes mainly participate in some vital pathways related to cancer pathogenesis, such as the focal adhesion, PI3K/Akt, p53, and mTOR signalling pathways. In summary, the identification of NPC patients with a four-miRNA signature may increase the prognostic value and provide reference information for precision medicine.

A Meta-Analysis of Vascular Endothelial Growth Factor for Nasopharyngeal Cancer Prognosis

Background: Vascular endothelial growth factor (VEGF) has been reported to serve as a promising prognostic marker in several cancers. This meta-analysis aims to assess the prognostic significance of VEGF in nasopharyngeal cancer (NPC).

Methods: We conducted a systematic literature search of PubMed, Embase, and the Cochrane Library for observational studies published until June, 2018 to identify observational studies on the prognostic effect of tissue VEGF expression or serum VEGF level on the survival of NPC. The primary outcome measure assessed was overall survival (OS). The secondary outcomes included disease-free survival (DFS) or progression-free survival (PFS). Summary hazard ratio (HR) and its 95% confidence interval (95% CI) were derived using a random-effects model.

Results: Out of 840 retrieved citations, 16 studies inclusive of 1,345 patients were included in the analysis of tissue VEGF expression and cancer survival. The pooled HRs for OS and DFS in patients with high VEGF expression were 2.07 (95% CI: 1.32–3.25) and 5.99 (95% CI: 2.66–13.48), respectively, with significant heterogeneity between studies (I² = 79.1% for OS and 50.2% for DFS). Tissue high VEGF expression was not significantly associated with short RFS, PFS, or MFS. Five studies also investigated the prognostic effect between serum VEGF level and patient survival and found that high serum VEGF level was significantly associated with short OS for patients with NPC (HR 2.47, 95% CI 1.16–5.28), but not with short PFS (HR 1.47, 95% CI 0.92–2.35).

Conclusions: Determination of tissue VEGF expression and serum VEGF level have the potential to serve as biomarkers and add prognostic information in NPC. Prospective analyses of associated data on VEGF expression and serum VEGF level in large NPC cohorts could be further conducted to advance our understanding of the relationship between VEGF and NPC outcomes.

Association between VEGF-460T/C gene polymorphism and clinical outcomes of nasopharyngeal carcinoma treated with intensity-modulated radiation therapy

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that plays a critical role in the development, metastasis, and recurrence of tumors. This study aims to determine the correlation of single-nucleotide polymorphisms in the VEGF gene with the prognosis of nasopharyngeal carcinoma (NPC). The VEGF -460T/C gene polymorphisms in the genomic DNA of the blood samples of 338 patients with NPC were investigated through polymerase chain reaction and direct DNA sequencing. Results showed a significant association between the -460C-allele carriers and the aggressive forms of NPC as defined by stages N2-3 (odds ratio =1.820, 95% confidence interval [CI]: 1.118-2.962, P=0.015). Furthermore, the VEGF -460T/C polymorphism was significantly associated with 3-year overall survival (OS), distant metastasis-free survival (DMFS), and progression-free survival (PFS) (T/C + C/C vs T/T: 3-year OS 78.8% vs 95.1%, P=0.003; 3-year DMFS 80.2% vs 90.6%, P=0.036; 3-year PFS 73.9% vs 86.7%, P=0.042) but was not associated with the local recurrence-free survival (LRFS) of the patients. The multivariate analysis indicated that the VEGF -460C-allele carrier was an independent significant prognostic factor for OS (hazard ratio [HR] 4.096, 95% CI: 1.333-12.591, P=0.014). N classification was an independent significant prognostic factor for DMFS in patients with locoregionally advanced NPC (HR 3.674, 95% CI: 1.144-11.792, P=0.029). However, neoadjuvant chemotherapy (NACT) followed by concurrent chemoradiotherapy (CCRT) was not superior to CCRT alone in terms of the 3-year OS, LRFS, DMFS, and PFS of patients with VEGF -460T/C polymorphism. In conclusion, the VEGF -460T/C gene polymorphism may negatively affect the clinical outcomes of patients with NPC and may be considered a potential prognostic factor for this disease.

Diagnostic values of serum cathepsin B and D in patients with nasopharyngeal carcinoma

Background

The diagnostic and prognostic significance of increased cathepsin B (CTSB) and cathepsin D (CTSD) concentration in the serum of cancer patients were evaluated for some tumor types. High expression of CTSD and CTSB was detected in biopsy tissues from nasopharyngeal carcinoma (NPC). However, whether CTSD and CTSB serve as diagnostic and prognostic markers of NPC remains unclear.

Methods

Serum samples were collected from 40 healthy volunteers and 80 NPC patients enrolled in the study. CTSB and CTSD in the serum samples were detected using enzyme-linked immunosorbent assay (ELISA). Concomitantly, the relationship between CTSB and CTSD concentrations and clinicopathological prognosis was assessed. The sensitivity and specificity of the two components in the diagnosis of NPC were evaluated in 80 NPC patients.

Results

ELISA analysis showed that in the sera obtained from NPC patients, the CTSB concentration was 12.5 ± 3.5 mg/L (median, 12.4 mg/L), and the CTSD concentration was 15.7 ± 8.7 mg/L (median, 14.7 mg/L). CTSB and CTSD levels were significantly higher in the NPC patient population compared to the healthy control population (p = 0.001; p = 0.001, respectively). The presence of CTSB and CTSD in the serum of the patients with NPC correlated with the tumor node metastasis (TNM) scores (p = 0.001). Other parameters were not identified to be of significance. Receiver operating characteristic (ROC) analysis showed that a cut off CTSB concentration of 12.4 mg/L had 61.9 % sensitivity and 63.2 % specificity in the prediction of progression-free survival (Area under the curve (AUC) = 0.525; 95 % CI, 39.7–65.2; p = 0.704); whereas a cut off CTSD concentration of 14.7 mg/L had 66.7 % sensitivity, and 58.5 % specificity (AUC = 0.552; 95 % CI, 42.3–68.1; p = 0.42).

Conclusions

Serum CTSB and CTSD concentrations were found to have a diagnostic value in NPC. However, the CTSB and CTSD serum levels had no prognostic role for the outcome in NPC patients.

CXCL12 genetic variants as prognostic markers in nasopharyngeal carcinoma

The chemokine receptor 4/chemokine ligand 12 (CXCR4/CXCL12) axis plays an important role in tumorigenesis, metastasis, and recurrence of tumors. Its single nucleotide polymorphisms (SNPs) are associated with patient survival in several types of cancer. However, the prognostic value of SNPs in nasopharyngeal carcinoma (NPC) has not been fully investigated. This retrospective study assessed the relationships between CXCR4 rs2228014 and CXCL12 rs1801157 polymorphisms and patient outcome in 222 patients newly diagnosed with NPC. The analysis found no significant correlation between the presence of both SNPs and clinicopathological factors. However, univariate analysis showed that N classification, clinical stage, and the CXCL12 rs1801157 polymorphism were significantly associated with distant metastasis-free survival (P=0.018, 0.028, and 0.013, respectively) and progression-free survival (P=0.007, 0.046, and 0.021, respectively). After adjusting clinicopathological factors, multivariate analysis identified CXCL12 rs1801157 as an independent prognostic factor for distant metastasis-free survival and progression-free survival (hazard ratio: 3.332; 95% confidence interval: 1.597-6.949; P=0.001 and hazard ratio: 2.665 95% confidence interval: 1.387-5.119; P=0.003, respectively). Our results suggest that CXCL12 rs1801157 AA genotype might serve as a potential prognostic factor in patients with NPC.

Prognostic Value of Molecular Markers and Implication for Molecular Targeted Therapies in Nasopharyngeal Carcinoma: An Update in an Era of New Targeted Molecules Development

The aim of the study was to evaluate the prognostic significance of molecular biomarkers which could provide information for more accurate prognostication and development of novel therapeutic strategies for nasopharyngeal carcinoma (NPC). NPC is a unique malignant epithelial carcinoma of head and neck region, with an intimate association with the Epstein-Barr virus (EBV). Currently, the prediction of NPC prognosis is mainly based on the clinical TNM staging; however, NPC patients with the same clinical stage often present different clinical outcomes, suggesting that the TNM stage is insufficient to precisely predict the prognosis of this disease. In this review, we give an overview of the prognostic value of molecular markers in NPC and discuss potential strategies of targeted therapies for treatment of NPC. Molecular biomarkers, which play roles in abnormal proliferation signaling pathways (such as Wnt/β-catenin pathway), intracellular mitogenic signal aberration (such as hypoxia-inducible factor (HIF)-1α), receptor-mediated aberrations (such as vascular endothelial growth factor (VEGF)), tumor suppressors (such as p16 and p27 activity), cell cycle aberrations (such as cyclin D1 and cyclin E), cell adhesion aberrations (such as E-cadherin), apoptosis dysregualtion (such as survivin) and centromere aberration (centromere protein H), are prognostic markers for NPC. Plasma EBV DNA concentrations and EBV-encoded latent membrane proteins are also prognostic markers for NPC. Implication of molecular targeted therapies in NPC was discussed. Such therapies could have potential in combination with different cytotoxic agents to combat and eradicate tumor cells. In order to further improve overall survival for patients with loco-regionally advanced NPC, the development of innovative strategies, including prognostic molecular markers and molecular targeted agents is needed.

Diagnostic value of serum M30 and M65 in patients with nasopharyngeal carcinoma

M30 and M65 are circulating fragments of cytokeratin 18 released during apoptotic cell death and regarded as markers of cell death in patients with various tumor types. Our aim was to investigate the clinical and prognostic significance of the serum M30 and M65 concentrations in patients with advanced nasopharyngeal carcinoma. Thirty-two patients with nasopharyngeal cancer and 32 control subjects were investigated. Serum samples were obtained on first admission before any treatment was initiated. Serum M30 and M65 concentrations were measured by quantitative enzyme-linked immunosorbent assay. Median serum M30 (181.5 vs. 45.5 U/L, p < 0.001) and M65 (384.2 vs. 179.1 U/L, p < 0.001) concentrations were significantly higher in patients with advanced nasopharyngeal carcinomas than in controls. receiver operating characteristic (ROC) analysis showed that a cutoff for M30 of 225 U/L had a sensitivity of 62.5% and a specificity of 73.9% (area under the curve (AUC) = 0.592, 95% confidence interval (CI) 35.3-83.2, p = 0.44), while a cutoff for M65 of 423.4 U/L had a sensitivity of 75.1% and a specificity of 65.6% (AUC = 0.562, 95 % CI 36.0-76.5, p = 0.60). However, serum M30 and M65 were not important prognostic factors for progression-free survival. There were no statistically significant correlations between serum M30 and M65 concentrations and clinicodemographical variables. Serum M30 and M65 concentrations were found to have a diagnostic value in nasopharyngeal cancer. However, neither M30 nor M65 serum levels played a prognostic role in the outcome in nasopharyngeal cancer patients.

Prognostic and predictive value of serum vascular endothelial growth factor (VEGF) in squamous cell carcinoma of the head and neck

INTRODUCTION

This study aimed to investigate the prognostic and predictive value of serum vascular endothelial growth factor (VEGF) in head and neck squamous cell carcinoma (HNSCC).

METHOD

Preoperative and 6-month postoperative serum VEGF levels were measured using a quantitative sandwich enzyme immunoassay technique in 55 consecutive patients with HNSCC and two control groups. The first control group included normal, healthy, age- and sex-matched individuals (n = 20), while the second control group included the patients who had history of HNSCC and were free of disease for at least 5 years (n = 25).

RESULTS

The mean baseline serum VEGF concentrations of the 55 patients with HNSCC and the first and the second control groups were 437.86, 42.56, and 48.03 pg/ml, respectively (P < 0.001). After a median follow-up of 75 months, 15 patients of the study group developed recurrent disease and 40 patients remained free of disease. The mean preoperative and 6-month postoperative serum VEGF levels for the 40 patients who did not have recurrent disease were respectively 327.69 and 153.50 pg/ml compared to 731.72 and 692.96 pg/ml for the 15 patients with recurrent disease (P < 0.001). High (≥540 pg/ml) serum VEGF level was associated with poor overall survival (P < 0.001). Moreover, multivariate analysis showed node stage (P < 0.001) and preoperative serum VEGF level (P = 0.020) as significant, independent prognostic factors for overall survival.

CONCLUSION

Preoperative or postoperative elevated serum levels of VEGF are highly predictive for disease recurrence and are associated with poor disease-free and overall survival of patients with HNSCC.

Reduced expression of Dicer11 is associated with poor prognosis in patients with nasopharyngeal carcinoma

Dicer11 plays an important role in generation of microRNA and is dysregulated in a variety of human cancers. The purpose of this study was to evaluate Dicer11 expression and its prognostic value in nasopharyngeal carcinoma (NPC). The protein expression of Dicer1 was examined by immunohistochemistry in 276 NPC specimens, and the mRNA levels of Dicer1 were analyzed by qRT-PCR in 56 NPC and 11 nasopharyngitis tissues. Cox regression analysis was used to identify independent prognostic factors, and a prognostic score model was constructed for survival prediction. Expression of Dicer1 was downregulated in NPC tissues at both the mRNA and the protein levels, and there was a notable positive correlation between the expression levels of Dicer1 mRNA and protein. Low Dicer1 expression was positively correlated with distant metastasis (P < 0.01) and death (P = 0.01). In addition, low expression of Dicer1 was significantly associated with poorer overall survival (HR, 2.32; 95 % CI 1.30-4.14; P < 0.01) and poorer distant metastasis-free survival (HR, 2.56; 95 % CI 1.39-4.74; P < 0.01). Furthermore, multivariate analysis showed that low expression of Dicer1 and tumor-node-metastasis (TNM) stage was independent prognostic indicators for NPC patients. A prognostic score model combining the Dicer1 expression and TNM stage had a better prognostic value than the TNM stage alone model or Dicer1 expression alone model (P < 0.05). Dicer1 was downregulated in NPC tissues at both the mRNA and the protein levels, and low expression of Dicer1 could be served as novel prognostic biomarker for NPC patients.

Elevated serum endostatin levels are associated with poor survival in patients with advanced-stage nasopharyngeal carcinoma

AIMS

To evaluate the prognostic value of serum endostatin levels in patients with advanced-stage nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

Between August 2003 and March 2005, 218 patients with advanced-stage NPC were enrolled in this study, including 70 patients in the training cohort and 148 in the validation cohort. The pre-treatment serum endostatin and vascular endothelial growth factor (VEGF) levels were measured using competitive enzyme immunoassays. For the normal control, serums samples from 20 healthy individuals were also collected.

RESULTS

Serum endostatin levels in the patients with advanced-stage NPC were significantly higher than those of controls, but VEGF levels were similar in the two groups. Univariate analysis revealed significant differences between the high and low endostatin level groups regarding 5 year overall survival (63.9% versus 90.5%; P = 0.003), progression-free survival (PFS) (50.2% versus 79.3%; P = 0.003) and distant metastasis-free survival (DMFS) (59.1% versus 85.3%; P = 0.01) in the training cohort. Using the same cut-off value generated from the training cohort, there were also significant unfavourable correlations between serum endostatin levels and overall survival (P = 0.001), PFS (P = 0.001) and DMFS (P = 0.002) in the second independent validation cohort. Multivariate analysis using the entire group (n = 218) revealed that the serum endostatin level was an independent unfavourable prognostic factor for overall survival (hazard ratio 4.8; 95% confidence interval 2.48-9.23; P < 0.0001), PFS (hazard ratio 3.44; 95% confidence interval 2.06-5.74; P < 0.0001) and DMFS (hazard ratio 3.65; 95% confidence interval 1.92-6.94; P < 0.0001) in patients with advanced-stage NPC. No associations were observed between the outcomes and the serum VEGF levels in patients with advanced-stage NPC.

CONCLUSIONS

High endostatin levels are associated with poor survival and this knowledge may improve the risk stratification of patients with advanced-stage NPC.

Current management of nasopharyngeal cancer

Management of nasopharyngeal carcinoma is one of the greatest clinical challenges. Appropriate detection is not easy because of its anatomical location; sensitive biomarkers in addition to endoscopic and radiological examinations would be valuable. One useful biomarker (particularly for nonkeratinizing carcinoma) is the plasma level of Epstein-Barr viral deoxyribonucleic acid, and its role as a tool for prognostication and monitoring disease progress is presented. Radiotherapy is the primary treatment modality, and using radiation therapy in combination with chemotherapy is recommended for the treatment of locoregionally advanced tumors. Intensity-modulated radiotherapy techniques with image guidance to ensure setup precision are recommended if resources allow; adaptive replanning should be considered if major deviations from the intended dose distribution occur during the treatment course. Most contemporary series have reported encouraging results, with locoregional control exceeding 90%; the key problem is distant failure. The therapeutic margin is extremely narrow. Although significant reduction of some toxicities (eg, xerostomia) and better quality of life is now achievable especially for early stages, the risk of major late toxicities remains substantial. This review will focus on the primary treatment: the current consensus and controversies in the treatment strategy for different stages, the choice of chemotherapy regimen, and the key factors for improving the therapeutic ratio of radiotherapy will be discussed. Summary of the current achievement and direction for future improvement will be presented.

LTBP-2 confers pleiotropic suppression and promotes dormancy in a growth factor permissive microenvironment in nasopharyngeal carcinoma

This study identified LTBP-2 as a pleiotropic tumor suppressor in nasopharyngeal carcinoma, which safeguards against critical malignant behaviors of tumor cells. LTBP-2 expression was significantly decreased or lost in up to 100% of NPC cell lines (7/7) and 80% of biopsies (24/30). Promoter hypermethylation was found to be involved in LTBP-2 silencing. Using a tetracycline-regulated inducible expression system, we unveiled functional roles of LTBP-2 in suppressing colony formation, anchorage-independent growth, cell migration, angiogenesis, VEGF secretion, and tumorigenicity. Three-dimensional culture studies suggested the involvement of LTBP-2 in maintenance of tumor cell dormancy in a growth factor favorable microenvironment.

Prognostic value of a microRNA signature in nasopharyngeal carcinoma: a microRNA expression analysis

BACKGROUND

MicroRNAs (miRNAs) can be used as prognostic biomarkers in many types of cancer. We aimed to identify miRNAs that were prognostic in patients with nasopharyngeal carcinoma.

METHODS

We retrospectively analysed miRNA expression profiles in 312 paraffin-embedded specimens of nasopharyngeal carcinoma from Sun Yat-sen University Cancer Center (Guangzhou, China) and 18 specimens of non-cancer nasopharyngitis. Using an 873 probe microarray, we assessed associations between miRNA signatures and clinical outcome in a randomly selected 156 samples (training set) and validated findings in the remaining 156 samples (internal validation set). We confirmed the miRNAs signature using quantitative RT-PCR analysis in 156 samples from a second randomisation of the 312 samples, and validated the miRNA signature in 153 samples from the West China Hospital of Sichuan University in Chengdu, China (independent set). We used the Kaplan-Meier method and log-rank tests to estimate correlations of the miRNA signature with disease-free survival (DFS), distant metastasis-free survival (DMFS), and overall survival.

FINDINGS

41 miRNAs were differentially expressed between nasopharyngeal carcinoma and non-cancer nasopharyngitis tissues. A signature of five miRNAs, each significantly associated with DFS, was identified in the training set. We calculated a risk score from the signature and classified patients as high risk or low risk. Compared with patients with low-risk scores, patients with high risk scores in the training set had shorter DFS (hazard ratio [HR] 2·73, 95% CI 1·46-5·11; p=0·0019), DMFS (3·48, 1·57-7·75; p=0·0020), and overall survival (2·48, 1·24-4·96; p=0·010). We noted equivalent findings in the internal validation set for DFS (2·47, 1·32-4·61; p=0·0052), DMFS (2·28, 1·09-4·80; p=0·030), and overall survival (2·87, 1·38-5·96; p=0·0051) and in the independent set for DFS (3·16, 1·65-6·04; p=0·0011), DMFS (2·39, 1·05-5·42; p=0·037), and overall survival (3·07, 1·34-7·01; p=0·0082). The five-miRNA signature was an independent prognostic factor. A combination of this signature and TNM stage had better prognostic value than did TNM stage alone in the training set (area under receiver operating characteristics 0·68 [95% CI 0·60-0·76] vs 0·60 [0·52-0·67]; p=0·013), the internal validation set (0·70 [0·61-0·78] vs 0·61 [0·54-0·68]; p=0·012), and the independent set (0·70 [0·62-0·78] vs 0·63 [0·56-0·69]; p=0·032).

INTERPRETATION

Identification of patients with the five-miRNA signature might add prognostic value to the TNM staging system and inform treatment decisions for patients at high risk of progression.

FUNDING

Science Foundation of Chinese Ministry of Health, National Natural Science Foundation of China, Pearl River Scholar Funded Scheme, Guangdong Key Scientific and Technological Innovation Program, Guangdong Natural Science Foundation, Fundamental Research Funds for the Central Universities.

Recently identified biomarkers that promote lymph node metastasis in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous cancer that arises in the upper aerodigestive tract. Despite advances in knowledge and treatment of this disease, the five-year survival rate after diagnosis of advanced (stage 3 and 4) HNSCC remains approximately 50%. One reason for the large degree of mortality associated with late stage HNSCC is the intrinsic ability of tumor cells to undergo locoregional invasion. Lymph nodes in the cervical region are the primary sites of metastasis for HNSCC, occurring before the formation of distant metastases. The presence of lymph node metastases is strongly associated with poor patient outcome, resulting in increased consideration being given to the development and implementation of anti-invasive strategies. In this review, we focus on select proteins that have been recently identified as promoters of lymph node metastasis in HNSCC. The discussed proteins are involved in a wide range of critical cellular functions, and offer a more comprehensive understanding of the factors involved in HNSCC metastasis while additionally providing increased options for consideration in the design of future therapeutic intervention strategies.