Leptin receptor expression and Gln223Arg polymorphism as prognostic markers in oral and oropharyngeal cancer.

The leptin gene product is released into the blood stream, passes through the blood-brain barrier, and finds the leptin receptor (LEPR) in the central nervous system. This hormone regulates food intake, hematopoiesis, inflammation, immunity, differentiation, and cell proliferation. The LEPR Gln223Arg polymorphism has been reported to alter receptor function and expression, both of which have been related with prognostics in several tumor types. Furthermore, several studies have shown a relationship between the Gln223Arg polymorphism and tumor development, and its role in oral and oropharyngeal squamous cell carcinoma is now well understood. In this study, 315 DNA samples were used for LEPR Gln223Arg genotyping and 87 primary oral and oropharyngeal squamous cell carcinomas were used for immunohistochemical expression analysis, such that a relationship between these and tumor development and prognosis could be established. Homozygous LEPR Arg223 was found to be associated with a 2-fold reduction in oral and oropharyngeal cancer risk. In contrast, the presence of the Arg223 allele in tumors was associated with worse disease-free and disease-specific survival. Low LEPR expression was found to be an independent risk factor, increasing the risk for lymph node metastasis 4-fold. In conclusion, the Gln223Arg polymorphism and LEPR expression might be valuable markers for oral and oropharyngeal cancer, suggesting that LEPR might serve as a potential target for future therapies.

Keratins 17 and 19 expression as prognostic markers in oral squamous cell carcinoma.

Five-year survival rates for oral squamous cell carcinoma (OSCC) are 30% and the mortality rate is 50%. Immunohistochemistry panels are used to evaluate proliferation, vascularization, apoptosis, HPV infection, and keratin expression, which are important markers of malignant progression. Keratins are a family of intermediate filaments predominantly expressed in epithelial cells and have an essential role in mechanical support and cytoskeleton formation, which is essential for the structural integrity and stability of the cell. In this study, we analyzed the expressions of keratins 17 and 19 (K17 and K19) by immunohistochemistry in tumoral and non-tumoral tissues from patients with OSCC. The results show that expression of these keratins is higher in tumor tissues compared to non-tumor tissues. Positive K17 expression correlates with lymph node metastasis and multivariate analysis confirmed this relationship, revealing a 6-fold increase in lymph node metastasis when K17 is expressed. We observed a correlation between K17 expression with disease-free survival and disease-specific death in patients who received surgery and radiotherapy. Multivariate analysis revealed that low expression of K17 was an independent marker for early disease relapse and disease-specific death in patients treated with surgery and radiotherapy, with an approximately 4-fold increased risk when compared to high K17 expression. Our results suggest a potential role for K17 and K19 expression profiles as tumor prognostic markers in OSCC patients.

MTHFR C677T and A1298C polymorphisms as predictors of radiotherapy response in head and neck squamous cell carcinoma.

The C677T and A1298C polymorphisms in methylene-tetrahydrofolate reductase (MTHFR), which regulates the release of active folate in the body, may have reduced activity. Given that folate participates in important intracellular pathways, such as nucleotide synthesis and biomolecule methylation, it seems plausible that patients with head and neck squamous cell carcinoma (HNSCC) may respond differently to radiotherapy treatments, based on genetic polymor-phisms. Therefore, this study sought to understand the role of these polymorphisms in HNSCC patient radiotherapy response. Genotypes were detected by PCR-RFLP after extraction of DNA from peripheral blood lymphocytes. Survival curves were analyzed by the Kaplan- Meier model, and significant differences were analyzed by the Wil-coxon test. Response to radiotherapy in patients with laryngeal SCC was significantly associated with the MTHFR C677T polymorphism (P = 0.030). Indeed, the presence of at least one T allele decreases the mortality rate up to 3-fold. Therefore, we propose that MTHFR C677T may represent a putative biomarker for radiotherapy prognosis in la-ryngeal SCC patients.

Prognostic significance of head and neck squamous cell carcinoma repair gene polymorphism.

The aims of this study were to analyze the polymorphisms XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, XPC Lys939Gln, ERCC1 Asn118Asn, and RAD51 -98G>C and to verify their influence on radiotherapy response and prognosis of patients with head and neck squamous cell carcinoma (HNSCC). Peripheral blood DNA was extracted from 311 patients and analyzed by PCR-RFLP. Our results showed that in irradiated oral and oropharyngeal patients, the 939Gln allele increased 6-fold local disease relapse risk (OR = 6.04; CI = 1.47-24.88) and over 2-fold the earliness of relapse (HR = 2.63; CI = 1.04-6.70). As for the XRCC3 polymorphism, multivariate analysis showed that the 241Met allele increases over 33-fold local relapse risk (OR = 33.64; CI = 3.23-350.85), over 12-fold earliness of relapse (HR = 12.55; CI = 2.47-63.73) and over 3-fold earliness of death (HR = 3.04; CI = 1.08-8.61). For polymorphism RAD51 -98, multivariate analysis showed that allele C increases over 3-fold the risk of relapse (OR = 3.13; CI = 1.12-8.78) and over 2-fold the earliness of relapse (HR = 2.84; CI = 1.25-6.47). For polymorphism XRCC1 Arg399Gln, multivariate analysis showed that the 399Gln allele increased the risk of local disease relapse for irradiated oral and oropharyngeal patients (OR = 3.35; CI = 1.10-10.13) by over 3-fold. Based on these results, we suggest that these polymorphisms may be useful markers of prognosis in HNSCC.

DAP1 high expression increases risk of lymph node metastases in squamous cell carcinoma of the oral cavity.

Death-associated protein 1 (DAP1) is a member of the DAP family. Its expression is associated with cell growth and normal death of the neoplastic cells, regulated by the mammalian target of the rapamycin protein. Activated DAP1 negatively regulates autophagy, which has been associated with the development and progression of several diseases, such as cancer, and with prognosis and survival of diverse tumor types. Therefore, in this study we analyzed DAP1 expression in 54 oral squamous cell carcinoma tumor samples and in 20 non-tumoral margins by immunohistochemistry. The results showed that DAP1 is more frequently expressed in tumor tissues compared with marginal non-tumoral cells. Additionally, high DAP1 expression is associated with a 4-fold increase in the risk of lymph node metastases. Our results suggest that the DAP1 protein can be used as a potential marker of lymph node metastases predisposition, helping define the best therapy for each patient to minimize risk of developing metastases.

FAS ligand expression in inflammatory infiltrate lymphoid cells as a prognostic marker in oral squamous cell carcinoma.

Currently, the most important prognostic factor in oral squamous cell carcinoma (OSCC) is the presence of regional lymph node metastases, which correlates with a 50% reduction in life expectancy. We have previously observed that expression of hypoxia genes in the tumor inflammatory infiltrate is statistically related to prognosis in OSCC. FAS and FASL expression levels in OSCC have previously been related to patient survival. The present study analyzed the relationship between FASL expression in the inflammatory infiltrate lymphoid cells and clinical variables, tumor histology, and prognosis of OSCC. Strong FASL expression was significantly associated with lymph node metastases (P = 0.035) and disease-specific death (P = 0.014), but multivariate analysis did not confirm FASL expression as an independent death risk factor (OR = 2.78, 95%CI = 0.81-9.55). Disease-free and disease-specific survival were significantly correlated with FASL expression (P = 0.016 and P = 0.005, respectively). Multivariate analysis revealed that strong FASL expression is an independent marker for earlier disease relapse and disease-specific death, with approximately 2.5-fold increased risk compared with weak expression (HR = 2.24, 95%CI = 1.08-4.65 and HR = 2.49, 95%CI = 1.04-5.99, respectively). Our results suggest a potential role for this expression profile as a tumor prognostic marker in OSCC patients.

Validation of methylation markers for diagnosis of oral cavity cancer.

PURPOSE: Activation of proto-oncogenes and inactivation of tumour suppressor genes are the major genetic alterations involved in carcinogenesis. The increase in methylation at the promoter region of a tumour suppressor gene can lead to gene inactivation, selecting cells with proliferative advantage. Thus, promoter hypermethylation is considered a marker in a variety of malignant tumours, including oral cavity. EXPERIMENTAL DESIGN: The methylation pattern of eight genes was evaluated in 40 oral cavity squamous cell carcinomas (OSCCs) and 40 saliva samples from healthy individuals by Q-MSP. Different combinations of genes were also assessed in order to identify gene panels that could better distinguish between OSCC and saliva samples. RESULTS: CCNA1, DAPK, DCC and TIMP3 methylation were highly specific for being found in the OSCC samples. Moreover, the combination of these genes improved detection when compared with single markers, reaching values of 92.5% for sensitivity and specificity (when using the panel CCNA1, DCC, TIMP3). Moreover, DAPK, DCC and TIMP3 were hypermethylated in nearly 90% of clinically T1 and T2 cases. CONCLUSION: The pursuing of this panel of hypermethylated genes is an important tool for the detection of individuals with OSCC. Moreover, the identification of these markers in early stages of OSCC shows the feasibility of using the panel on saliva as possible biomarkers for early diagnosis. The lack of association between the methylation status of these genes and clinical characteristics shows that they are able to distinguish OSCC cases irrespective of social and clinical factors (gender, age, human papillomavirus (HPV) status, clinical stage, vascular embolisation and perineural invasion).

Papel da proteína Mx1 na resposta a interferons e no processo neoplásico / Role of Mx1 protein in the response to interferons and neoplastic process

A proteína Mx1 é codificada por um gene induzido por interferon e compartilha a organização de seus domínios, a capacidade de homo-oligomerização e associação com membranas com as grandes dinaminas GTPases. A proteína Mx1 está envolvida na resposta contra um grande número de vírus de RNA, como aqueles pertencentes à família Buniavírus e o vírus influenza. Curiosamente, o gene MX1 foi encontrado como silenciado por metilação em diversos processos neoplásicos, incluindo carcinomas de cabeça e pescoço de células escamosas. Neste cenário, o silenciamento gênico de MX1 está associado à imortalização de uma série de linhagens celulares neoplásicas. Assim, Mx1 se destaca como uma das principais proteínas envolvidas nas respostas imunes induzidas por interferon e também desempenha um importante papel no controle do ciclo celular. Aqui discutimos os aspectos funcionais da proteína Mx1 abordando sua atividade antiviral, organização estrutural, envolvimento com neoplasias e, principalmente, os aspectos funcionais obtidos pela determinação de seus parceiros celulares.

The Mx1 protein is encoded by an interferon-induced gene and shares domain organization, homo-oligomerization capacity and membrane association with the large dynamin-like GTPases. The Mx1 protein is involved in the response to a large number of RNA viruses, such as the bunyavirus family and the influenza virus. Interestingly, it has also been found as a methylation-silenced gene in several types of neoplasm, including head and neck squamous cell carcinoma. In this scenario, MX1 gene silencing is associated with immortalization in several neoplastic cell lines. Thus, Mx1 stands out as one of the key proteins involved in interferon-induced immune response and also plays an important role in cell cycle control. Here we discuss some of the functions of the Mx1 protein, including its antiviral activity, protein folding and involvement in neoplasia, as well as those revealed by investigating its cellular partners.

Genomics and proteomics approaches to the study of cancer-stroma interactions.

BACKGROUND: The development and progression of cancer depend on its genetic characteristics as well as on the interactions with its microenvironment. Understanding these interactions may contribute to diagnostic and prognostic evaluations and to the development of new cancer therapies. Aiming to investigate potential mechanisms by which the tumor microenvironment might contribute to a cancer phenotype, we evaluated soluble paracrine factors produced by stromal and neoplastic cells which may influence proliferation and gene and protein expression. METHODS: The study was carried out on the epithelial cancer cell line (Hep-2) and fibroblasts isolated from a primary oral cancer. We combined a conditioned-medium technique with subtraction hybridization approach, quantitative PCR and proteomics, in order to evaluate gene and protein expression influenced by soluble paracrine factors produced by stromal and neoplastic cells. RESULTS: We observed that conditioned medium from fibroblast cultures (FCM) inhibited proliferation and induced apoptosis in Hep-2 cells. In neoplastic cells, 41 genes and 5 proteins exhibited changes in expression levels in response to FCM and, in fibroblasts, 17 genes and 2 proteins showed down-regulation in response to conditioned medium from Hep-2 cells (HCM). Nine genes were selected and the expression results of 6 down-regulated genes (ARID4A, CALR, GNB2L1, RNF10, SQSTM1, USP9X) were validated by real time PCR. CONCLUSIONS: A significant and common denominator in the results was the potential induction of signaling changes associated with immune or inflammatory response in the absence of a specific protein.

Annexin A1 subcellular expression in laryngeal squamous cell carcinoma.

AIMS: Annexin A1 (ANXA1) is a soluble cytoplasmic protein, moving to membranes when calcium levels are elevated. ANXA1 has also been shown to move to the nucleus or outside the cells, depending on tyrosine-kinase signalling, thus interfering in cytoskeletal organization and cell differentiation, mostly in inflammatory and neoplastic processes. The aim was to investigate subcellular patterns of immunohistochemical expression of ANXA1 in neoplastic and non-neoplastic samples from patients with laryngeal squamous cell carcinomas (LSCC), to elucidate the role of ANXA1 in laryngeal carcinogenesis. METHODS AND RESULTS: Serial analysis of gene expression experiments detected reduced expression of ANXA1 gene in LSCC compared with the corresponding non-neoplastic margins. Quantitative polymerase chain reaction confirmed ANXA1 low expression in 15 LSCC and eight matched normal samples. Thus, we investigated subcellular patterns of immunohistochemical expression of ANXA1 in 241 paraffin-embedded samples from 95 patients with LSCC. The results showed ANXA1 down-regulation in dysplastic, tumourous and metastatic lesions and provided evidence for the progressive migration of ANXA1 from the nucleus towards the membrane during laryngeal tumorigenesis. CONCLUSIONS: ANXA1 dysregulation was observed early in laryngeal carcinogenesis, in intra-epithelial neoplasms; it was not found related to prognostic parameters, such as nodal metastases.

Purification, biochemical and functional characterization of miliin, a new thiol-dependent serine protease isolated from the latex of Euphorbia milii.

Miliin, a new thiol-dependent serine protease purified from the latex of Euphorbia milii possesses a molecular weight of 79 kDa, an isoelectric point of 4.3 and is optimally active at 60 degrees C in the pH range of and 7.5-11.0. Activity tests indicate that milliin is a thiol-dependent serine protease.

Neurofibromin: a general outlook.

Neurofibromin is a cytoplasmic protein that is predominantly expressed in neurons, Schwann cells, oligodendrocytes, astrocytes and leukocytes. It is encoded by the gene NF1, located on chromosome 17, at q11.2, and has different biochemical functions, including association to microtubules and participation in several signaling pathways. Alterations in this protein are responsible for a phacomatosis named neurofibromatosis type 1.

LHX6 is a sensitive methylation marker in head and neck carcinomas.

Head and neck cancer remains a morbid and often fatal disease and at the present time few effective molecular markers have been identified. The purpose of the present work was to identify new molecular markers for head and neck squamous cell carcinoma (HNSCC). We applied methylation-sensitive arbitrarily primed PCR (MS/AP-PCR) to isolate sequences differentially methylated in HNSCC. The most frequently hypermethylated fragment we found maps close to a cytosine guanine dinucleotide (CpG) island on chromosome 9q33.2, and hypermethylation of this CpG island was associated with transcriptional silencing of an alternative transcript of the LHX6 gene. Using combined bisulfite restriction analysis (COBRA), hypermethylation of this fragment was detected in 13 of 14 (92.8%) HNSCC cell lines studied and 21 of 32 (65.6%) primary tumors, whereas little or no methylation was seen in 10 normal oral mucosa samples. We extended this investigation to other cancer cell lines and methylation was found in those derived from colon, breast, leukemia and lung, and methylation was also found in 12/14 primary colon tumors. These findings suggest that differentially methylated (DIME)-6 hypermethylation is a good cancer marker in HNSCC as well as in other kinds of neoplasias and confirm the importance of searching for markers of epigenetic dysregulation in cancer.

High frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis in Brazilian patients with neurofibromatosis type 1.

A clinical study of Brazilian patients with neurofibromatosis type 1 (NF1) was performed in a multidisciplinary Neurofibromatosis Program called CEPAN (Center of Research and Service in Neurofibromatosis). Among 55 patients (60% females, 40% males) who met the NIH criteria for the diagnosis of NF1, 98% had more than six café-au-lait patches, 94.5% had axillary freckling, 45% had inguinal freckling, and 87.5% had Lisch nodules. Cutaneous neurofibromas were observed in 96%, and 40% presented plexiform neurofibromas. A positive family history of NF1 was found in 60%, and mental retardation occurred in 35%. Some degree of scoliosis was noted in 49%, 51% had macrocephaly, 40% had short stature, 76% had learning difficulties, and 2% had optic gliomas. Unexpectedly high frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a) by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A) and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G) were identified. These data were recently published.

High frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis in Brazilian patients with neurofibromatosis type 1

A clinical study of Brazilian patients with neurofibromatosis type 1 (NF1) was performed in a multidisciplinary Neurofibromatosis Program called CEPAN (Center of Research and Service in Neurofibromatosis). Among 55 patients (60 percent females, 40 percent males) who met the NIH criteria for the diagnosis of NF1, 98 percent had more than six café-au-lait patches, 94.5 percent had axillary freckling, 45 percent had inguinal freckling, and 87.5 percent had Lisch nodules. Cutaneous neurofibromas were observed in 96 percent, and 40 percent presented plexiform neurofibromas. A positive family history of NF1 was found in 60 percent, and mental retardation occurred in 35 percent. Some degree of scoliosis was noted in 49 percent, 51 percent had macrocephaly, 40 percent had short stature, 76 percent had learning difficulties, and 2 percent had optic gliomas. Unexpectedly high frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a) by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A) and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G) were identified. These data were recently published.

Association of apolipoprotein E polymorphism in late-onset Alzheimer's disease and vascular dementia in Brazilians.

The genetic basis for dementias is complex. A common polymorphism in the apolipoprotein E (APOE) gene is considered to be the major risk factor in families with sporadic and late-onset Alzheimer's disease as well as in the general population. The distribution of alleles and genotypes of the APOE gene in late-onset Alzheimer's disease (N = 68), other late-life dementias (N = 39), and in cognitively normal controls (N = 58) was determined, as also was the risk for Alzheimer's disease associated with the epsilon4 allele. Peripheral blood samples were obtained from a total of 165 individuals living in Brazil aged 65-82 years. Genomic DNA was amplified by the polymerase chain reaction and the products were digested with HhaI restriction enzyme. APOE epsilon2 frequency was considerably lower in the Alzheimer's disease group (1%), and the epsilon3 allele and epsilon3/epsilon3 genotype frequencies were higher in the controls (84 and 72%, respectively) as were the epsilon4 allele and epsilon3/epsilon4 genotype frequencies in Alzheimer's disease (25 and 41%, respectively). The higher frequency of the epsilon4 allele in Alzheimer's disease confirmed its role as a risk factor, while epsilon2 provided a weak protection against development of the disease. However, in view of the unexpectedly low frequency of the epsilon4 allele, additional analyses in a more varied Brazilian sample are needed to clarify the real contribution of apolipoprotein E to the development of Alzheimer's disease in this population.

Association of apolipoprotein E polymorphism in late-onset Alzheimer's disease and vascular dementia in Brazilians

The genetic basis for dementias is complex. A common polymorphism in the apolipoprotein E (APOE) gene is considered to be the major risk factor in families with sporadic and late-onset Alzheimer's disease as well as in the general population. The distribution of alleles and genotypes of the APOE gene in late-onset Alzheimer's disease (N = 68), other late-life dementias (N = 39), and in cognitively normal controls (N = 58) was determined, as also was the risk for Alzheimer's disease associated with the epsilon4 allele. Peripheral blood samples were obtained from a total of 165 individuals living in Brazil aged 65-82 years. Genomic DNA was amplified by the polymerase chain reaction and the products were digested with HhaI restriction enzyme. APOE epsilon2 frequency was considerably lower in the Alzheimer's disease group (1 percent), and the epsilon3 allele and epsilon3/epsilon3 genotype frequencies were higher in the controls (84 and 72 percent, respectively) as were the epsilon4 allele and epsilon3/epsilon4 genotype frequencies in Alzheimer's disease (25 and 41 percent, respectively). The higher frequency of the epsilon4 allele in Alzheimer's disease confirmed its role as a risk factor, while epsilon2 provided a weak protection against development of the disease. However, in view of the unexpectedly low frequency of the epsilon4 allele, additional analyses in a more varied Brazilian sample are needed to clarify the real contribution of apolipoprotein E to the development of Alzheimer's disease in this population