Hypermethylation status of DAPK, MGMT and RUNX3 in HPV negative oral and oropharyngeal squamous cell carcinoma.

Squamous cell carcinoma of the oral cavity and oropharynx is the sixth most common type of cancer in the world. During tumorigenesis, gene promoter hypermethylation is considered an important mechanism of transcription silencing of tumor suppressor genes, such as DAPK, MGMT and RUNX3. These genes participate in signaling pathways related to apoptosis, DNA repair and proliferation whose loss of expression is possibly associated with cancer development and progression.

Polymorphisms in methylenetetrahydrofolate reductase and cystathionine beta-synthase in oral cancer - a case-control study in southeastern Brazilians.

Introduction: Oral squamous cell carcinoma (OSCC) is a serious public health problem, due to its high mortality rate and worldwide rising incidence. OSCC susceptibility is mediated by interactions between genetic and environmental factors. Studies suggest that genetic variants encoding enzymes involved in folate metabolism may modulate OSCC risk by altering DNA synthesis/repair and methylation process.

Promoter hypermethylation in primary squamous cell carcinoma of the oral cavity and oropharynx: a study of a Brazilian cohort.

Epigenetic silencing of cancer-related genes plays an important role in oral/oropharyngeal squamous cell carcinoma (OSCC). We evaluated promoter hypermethylation of 4 cancer-related genes in OSCCs of a Brazilian cohort and determined its relationship with exposure to alcohol, tobacco, HPV infection and clinicopathological parameters. CDKN2A (cyclin-dependent kinase inhibitor 2A or p16), SFN (stratifin or 14-3-3 σ), EDNRB (endothelin receptor B) and RUNX3 (runt-related transcript factor-3) had their methylation patterns evaluated by MSP analysis in OSCC tumors (n = 45).

Methylation analysis of cancer-related genes in non-neoplastic cells from patients with oral squamous cell carcinoma.

Early detection of Oral Squamous Cell Carcinoma (OSCC) is important to reduce mortality rates and to help provide successful cancer treatment. Hypermethylation of CpG islands is a common epigenetic mechanism that leads to gene silencing in tumors and could be a useful biomarker in OSCC. Abnormal DNA hypermethylation can occur very early in cancer development and may be induced by exposure to environmental carcinogens.

Comparison of DGGE and immunohistochemistry in the detection of TP53 variants in a Brazilian sample of sporadic breast tumors.

The presence of TP53 gene mutations in breast cancer has been associated with worse prognosis. These mutations interfere with the ability of the p53 protein, a transcription factor, to regulate the expression of target genes. Unlike the wild-type protein, which is rapidly degraded in cells, mutated forms have increased half-life and accumulate in tumor cells.

Prevalence of 35delG/GJB2 and del (GJB6-D13S1830) mutations in patients with non-syndromic deafness from a population of Espírito Santo-Brazil.

Unlabelled: Mutations in GJB2 gene are the leading cause of deafness in autosomal recessive inheritance, and the 35delG mutation is the most common in many ethnic groups. Besides the 35delG mutation in homozygosis, the mutation is also found in compound heterozygosis, coupled with other mutations in genes GJB2 and GJB6.

Aim: To determine the prevalence of 35delG/GJB2 and del (GJB6-D13S1830) mutations in patients with sensorineural hearing impairment in residents from the Espirito Santo state, Brazil.

Mutation analysis of GJB2 and GJB6 genes in Southeastern Brazilians with hereditary nonsyndromic deafness.

In developed countries deafness has a genetic cause in over 60% of the cases. Contrastingly, in Brazil, it is estimated that only 16% of all deafnesses are caused by genetic factors. Among hereditary hearing deficiencies, approximately half is caused by mutations in the Gap Junction Protein Beta-2 (GJB2) gene, which encodes the protein Connexin 26 (Cx26).