Association of Peripheral Blood RASSF1A and CDKN2A Methylation Status with Smoking Behaviour in Nasopharyngeal Carcinoma

Abstract

BACKGROUND: Hypermethylation of RASSF1A and CDKN2A is one of epigenetic factor underlies nasopharyngeal carcinoma (NPC) development. Smoking behavior as an NPC’s risk factor causes aberrant DNA methylation. RASSF1A and CDKN2A promoter hypermethylation from peripheral blood cells correlates with smoking behavior. The use of body fluids including peripheral blood as a specimen for DNA methylation analyzes are widely developed, as less invasive method compared to the use of tissue biopsy. This study aims to observe the association between RASSF1A and CDKN2A methylation in peripheral blood and smoking behavioramong NPC patients.METHODS: Newly diagnosed NPC subjects were recruited from ear-nose-throat (ENT) outpatient clinic of Dr. Sardjito Hospital, Yogyakarta. DNA from buffycoat of 19 smokers and 20 non-smokers NPC’s patients were isolated. Bisulphite modification was applied to 500 ng of the isolated DNA. The methylation status was detected by MSP (methylation-specific polymerase chain reaction (PCR)). The association between smoking status and promoter hypermethylation was analysis using Chi-Square test.RESULTS: MSP analysis of RASSF1A showed that 68.42% smoker and 75% non-smoker NPC’s patients were methylated. MSP analysis of CDKN2A showed that 21.05% smoker and 25% non-smoker NPC’s patients were methylated. There was no association between smoking behavior with RASSF1A and CDKN2A methylation (p>0.05).CONCLUSION: Statistical analysis showed that smoking behavior is not associated with methylation of RASSF1A and CDKN2A among NPC’s patients.KEYWORDS: DNA methylation, CDKN2A, RASSF1A, Nasopharyngeal carcinoma, Smoking

Current Status and Future Perspectives about Molecular Biomarkers of Nasopharyngeal Carcinoma

“…Many studies have demonstrated cigarette smoking confers a two- to six-fold higher risk of NPC development, with the risk increasing the longer one is a smoker and the more cigarettes one smokes in a day [ 107 , 108 , 109 , 110 , 111 ]. Cigarette smoke is known to contain carcinogenic compounds that cause DNA damage (genome), recruit DNA methyltransferase, hypoxia, activate DNA-binding proteins, and can eventually lead to genome alteration (mutation), disruption of cellular metabolic processes, and epigenetic change [ 112 , 113 ].…”

“…The epigenetic effect of cigarette smoking has an impact on TSGs and oncogenes through DNA methylation. For example, hypermethylation in RASSF1A and CDKN2A is one of the epigenetic changes under NPC development [ 113 ]. A study reported that RASSF1A and CDKN2A were upregulated among smokers compared to non-smokers [ 116 ].…”

NPC-Exosome Carry Wild and Mutant-type p53 among Nasopharyngeal Cancer Patients

“…The global NPC incidence is 1.7/100,000 per year. Estimated incidence of NPC in Indonesia is quite high, which is 8.3/100,000 per year (1,2). On the other hand, the incidence was rare in Europa and America.…”