Loss of imprinting and loss of heterozygosity on 11p15.5 in head and neck squamous cell carcinomas

Background. IGF2 and H19 are reciprocal imprinted genes with paternal and maternal monoallelic expression, respectively. This is interesting, because IGF2 is known as a growth factor, and H19 encodes a RNA with putative tumor suppressor action. Furthermore, IGF2 and H19 are linked genes located on chromosome 11p15.5, a common site of loss of heterozygosity in human cancers.Methods. We performed an allelic-typing assay using a PCR-RFLP-based method for identification of heterozygous Informative cases in head and neck squamous cell carcinomas. Tumoral total RNA was extracted from each of the heterozygotes and further studied by RT-PCR analysis.Results. We detected the expression of the IGF2 gene in 10 of 10 informative cases. Two cases exhibited LOI of the IGF2 gene as evidenced by biallelic expression, and in another case, LOH was coupled with monoallelic expression of this growth factor. LOI for the H19 gene was observed in 1 of 14 informative samples analyzed. In this case, we also detected parallel mono-allelic expression of the IGF2 gene. Down-regulation of the H19 gene was observed in 10 of 14 cases.Conclusion. These findings support the hypothesis that H19 may be a tumor suppressor gene involved In head and neck carcinogenesis. Furthermore, our data showed that genetic and epigenetic chances at 11p15.5 could lead to abnormal expression of imprinted genes in HNSCC. (C) 2001 John Wiley & Sons, Inc.

Analysis of human papillomavirus prevalence and TP53 polymorphism in head and neck squamous cell carcinomas

Head and neck squamous cell carcinoma is a disease associated with tobacco and alcohol abuse. There is evidence that the oncogenic human papillomavirus (HPV) may also be a risk for upper aerodigestive tract cancers. High-risk HPVs encode two early proteins, E6 and E7, that can bind to p53 and pRb, respectively, and induce its degradation or inactivation. The TP53 gene has a single polymorphism at codon 72 of exon 4 that encodes either arginine (Arg) or proline (Pro). The purpose of this study was to evaluate the role of HPV infection and TP53 polymorphism in head and neck cancer. We analyzed 50 tumors, as well swabs of oral mucosa front 142 control individuals, with a polymerase chain reaction technique. The prevalence of HPV in controls was 10.6% and in cancer specimens 16%. The frequency distribution of genotypes in controls was 50% Arg/Arg, 43% Arg/ Pro and 7% Pro/Pro; in tumors, it was 52% Arg/Arg, 32% Arg/Pro, and 16% Pro/Pro. Contrary to the results of some studies on cervical cancer, no association between any TP53 genotype or allele and the development of head and neck cancer was observed, regardless of HPV status, except for the Pro/Pro genotype, which is associated with the absence of HPV. The arginine allele appears to protect against head and neck cancers. Also, the data showed that HPV infection results in no increased risk of developing head and neck tumors. (C) 2004 Elsevier B.V. All rights reserved.

Physical education undergraduates and dental trauma knowledge

The aim of the present study was to assess the level of knowledge of undergraduates from the College of Physical Education (Toledo, Aracatuba) concerning dental avulsion injuries. Data showed that 95% of the respondents did not know what dental avulsion is, 73.5% said they know how to define dental replantation, however, only 26% were able to do it correctly. When asked about first emergency measures after an avulsion, 50% of the respondents said they know what they should do, and the most cited measure was to seek a dentist. When asked about optimal storage media, 45.5% would keep it in a favorable one, and 28% did not know where to keep the tooth until treatment. Only 25.6% indicated a suitable extra-oral time for replantation; 90.3% of the respondents had received no advice about the emergency management of dental avulsion; 90% said they consider this an important and necessary subject. The results indicated that educational campaigns are necessary to improve the emergency management of dental injuries by those future P.E. professors for a better prognosis of dental replantation.

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.

Second Primary Tumors in Patients with Head and Neck Cancer

This is a review on second primary tumors in patients with head and neck cancer. These patients have a high risk of developing other cancers simultaneously or subsequently. The incidence of multiple primary tumors in this population can be as high as 27%. Recurrences are the most common cause of treatment failure within the first 2 years of follow-up. After the third year the diagnosis of a second primary tumor becomes the most important cause of morbimortality in head and neck cancer patients, especially in those treated for cancers early diagnosed. Most second primary tumors occur in the upper aerodigestive tract (40%-59%), lung (31%-37.5%), and esophagus (9%-44%). Patients who develop second primary tumor have a significant reduction of survival expectancy.

Analysis of the TAX1BP1 gene in head and neck cancer patients

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)