Classical and molecular cytogenetic analysis in head and neck squamous cell carcinomas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

CYP1A2*1C, CYP2E1*5B, and GSTM1 polymorphisms are predictors of risk and poor outcome in head and neck squamous cell carcinoma patients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

microRNA evaluation of unknown primary lesions in the head and neck

Unknown primary malignancy in the head and neck is not an infrequent diagnosis for patients with metastatic cervical lymph nodes. Although linked with a relatively good prognosis following radiation treatment, widespread radiation is coupled with significant morbidity. Altered microRNA (miRNA) expression has been associated with both cancer progression and metastasis. We sought to determine whether miRNA expression analysis could be used as a diagnostic tool to discover the primary site of malignancy, within the head and neck. We used quantitative real-time PCR to identify miRNA expression profiles of squamous cell carcinoma of the tonsil, base of tongue and post-nasal space, as well as their corresponding metastatic lymph nodes, from 6 patients. Our results revealed that each cancer maintained its expression profile between the primary site and the nodal metastasis (r = 0.82, p < 0.0001). In addition, each anatomical sub-site maintained a distinct miRNA profile between individual patients (r = 0.79, p < 0.0001). Finally, between sub-sites, the miRNA profiles were distinct (p < 0.0001). As proof of principle, our study provides an indication that miRNA expression analysis may be useful to compare the primary lesion and local metastatic disease. This may be clinically relevant to predict the primary site of origin of metastatic disease, when the primary site remains obscure.

Methylation profile of genes CDKN2A (p14 and p16), DAPK1, CDH1, and ADAM23 in head and neck cancer

Hypermethylation in the promoter region has been associated with a loss of gene function that may give a selective advantage to neoplastic cells. In this study, the methylation pattern of genes CDKN2A (alias p14, p14(ARF), p16, p16(INK4a)), DAPK1, CDH1, and ADAM23 was analyzed in 43 samples of head and neck tumors using methylation-specific polymerase chain reaction. In the oropharynx, there was a statistically significant association between hypermethylation of the DAPK1 gene and the occurrence of lymph node metastases, and in the larynx there was statistically significant evidence of an association between hypermethylation of the ADAM23 gene and advanced stages of the tumors. Thus, a correlation was observed between hypermethylation of the promoter region of genes DAPK1 and ADAM23 and the progression of head and neck cancer. (c) 2007 Elsevier B.V. All rights reserved.

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/APPCR) 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.

Epigenetic Silencing of CRABP2 and MX1 in Head and Neck Tumors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative genomic hybridization analysis detects frequent over-representation of DNA sequences at 3q, 7p, and 8q in head and neck carcinomas

Comparative genomic hybridization (CGH) was used to identify chromosomal imbalances in 19 samples of squamous cell carcinoma of the head and neck (HNSCC). The chromosome arms most often or er-represented were 3q (48%), 8q (42%), and 7p (32%); in many cases, these changes were observed at high copy number. Other commonly over-represented sites were 1q, 2q, 6p, 6q, and 18q. The most frequently under-represented segments were 3p and 22q. Loss of heterozygosity of two polymorphic microsatellite loci from chromosome 22 was observed in two tongue tumors, in agreement with the CGH analysis. Gains of 1q and 2q material were detected in patients exhibiting a clinical history of recurrence and/or metastasis followed by terminal disease. This association suggests that gain of 1q and 2q map be a new marker of head and neck tumors with a refractory clinical response. (C) 2000 Elsevier B.V. All rights reserved.

Clinicopathological analysis of head and neck chondrosarcoma: three case reports and literature review

Chondrosarcoma (CHS) is a malignant neoplasm characterized by the formation of cartilaginous matrix by neoplastic cells, with a high propensity for local recurrences. Head and neck CHS is rare, accounting for less than 12% of all cases of CHS, usually affecting the maxilla. The majority of affected patients are in the fourth decade of life, with a slight predilection for male patients. A painless swelling is commonly the most frequent complaint. Surgery with wide en-bloc resection is the preferred treatment for CHS; radiotherapy and chemotherapy are usually palliative options. Owing to its rarity, there are few clinical series evaluating the biological behaviour of head and neck CHS. The aim of this study is to analyse the clinicopathological characteristics of head and neck CHS by reporting 3 new cases of this neoplasia affecting the jaw bones and reviewing the clinical series previously published in the English literature.

Analysis of the TAX1BP1 gene in head and neck cancer patients

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Distinct regions of loss of heterozygosity on 22q at different sites of head and neck squamous cell carcinomas

Background: Frequent loss of heterozygosity (LOH) has been reported in many types of cancer, including head and neck carcinomas. Somatic deletions involving specific chromosomal regions are strongly associated with inactivation of the allele of a tumor suppressor gene located within the deleted region. In most studies concerning LOH in head and neck squamous cell carcinomas (HNSCC) the different anatomical sites are not distinguished. The behavior of tumors arising at various sites differs significantly, however, suggesting different intrinsic tumor properties. In this study we compared the LOH on 22q and its relationship to clinicopathological parameters at the three major sites of HNSCC: oral cavity, larynx and pharynx. Material/Methods: LOH and microsatellite instability (MSI) were studied using seven polymorphic microsatellite markers mapped to the 22q11-q13.3 region in 37 oral, 32 laryngeal, and 31 pharyngeal carcinomas. Results: Two separate regions of LOH were identified in the laryngeal (22q11.2-12.1) and oral cavity (22q13.1-13.31) tumors. When the different anatomical sites were compared, a statistically significant difference was found between the presence of LOH at D22S421 (p<0.001), D22S315 (p=0.014) and D22S929 (p=0.026) in the laryngeal tumors. Conclusions: These data suggest that distinct regions on 22q are involved in LOH in oral cavity and laryngeal tumorigenesis but do not support a similar association between the development of pharyngeal tumors and genes located on 22q. These findings implicate the presence of different tumor suppressor genes mapping to distinct regions on chromosome 22q in oral and laryngeal carcinomas.

Influence of preventive dental treatment on mutans streptococci counts in patients undergoing head and neck radiotherapy

The aim of this study was to evaluate the influence of chlorhexidine gluconate, sodium fluoride and sodium iodine on mutans streptococci counts in saliva of irradiated patients. Forty-five patients were separated into three experimental groups and received chlorhexidine (0.12%), sodium fluoride (0.5%) or sodium iodine (2%), which were used daily during radiotherapy and for 6 months after the conclusion of the treatment. In addition, a fourth group, composed by 15 additional oncologic patients, who did not receive the mouthwash or initial dental treatment, constituted the control group. Clinical evaluations were performed in the first visit to dental clinic, after initial dental treatment, immediately before radiotherapy, after radiotherapy and 30, 60, 90 days and 6 months after the conclusion of radiotherapy. After clinical examinations, samples of saliva were inoculated on SB20 selective agar and incubated under anaerobiosis, at 37oC for 48 h. Total mutans streptococci counts were also evaluated by using real-time PCR, through TaqMan system, with specific primers and probes for S. mutans and S. sobrinus. All preventive protocols were able to reduce significantly mutans streptococci counts, but chlorhexidine gluconate was the most effective, and induced a significant amelioration of radiotherapy side effects, such as mucositis and candidosis. These results highlights the importance of the initial dental treatment for patients who will be subjected to radiotherapy for head and neck cancer treatment.