Profile methylation of the RASSF-1A exon 1 in actinic cheilitis and squamous cell carcinoma of the lower lip using pyrosequencing technique

• Grant number: 11/21915-1
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2012
• End date: July 31, 2014
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Luiz Paulo Kowalski
• Grantee: Luiz Paulo Kowalski
• Host Institution: A C Camargo Cancer Center. Fundação Antonio Prudente (FAP). São Paulo , SP, Brazil
• Associated researchers: Estela Kaminagakura Tango

Abstract

Chronic exposure to UVB radiation can cause hypermethylation and silencing of tumor suppressor gene RASSF-1A, which encodes a protein modulator of several functions essential for cell cycle controlling. The aim of this study will be investigate the clinical significance of the methylation profile of the RASSF-1A exon 1 and its protein expression in actinic cheilitis and squamous cell carcinoma of the lower lip vermilion. Demographic and clinicopathological data will be collected from medical records of patients with confirmed diagnosis. The DNA of 90 paraffin tissue samples will be extracted and subjected to treatment with sodium bisulfite. The DNA treated and intact will be submitted to amplification by PCR using the primer specific for RASSF-1A exon 1. The sequencing by synthesis reaction of complementary strand will be performed automatically, the signal emitted during the reaction will be detected by a camera and converted into a pirograma to form peaks. The cut off for considering that this region is hypermethylated will be Ã10%. Later, immunohistochemical reactions against-RASSF-1A will be carried out to validate the results. Statistical analyses of associations between variables will be performed by the Fisher's exact test and Chi square test (with significance set for P<0.05). For cases of carcinoma, the Kaplan Meier will be applied to verify the actuarial survival rates and log-rank test will be used to compare survival curves. (AU)