Microsatellite GTn-repeat polymorphism in the promoter of heme oxygenase-1 gene is an independent predictor of tumor recurrence in male oral squamous cell carcinoma patients

BACKGROUND: Transcriptional activity of the heme oxygenase-1 gene (HMOX-1) is modulated by a GTn-repeat promoter polymorphism. The long GTn-repeat allele has been previously reported to be associated with increased risk of oral squamous cell carcinoma (OSCC) in male areca chewer and short GTn-repeat allele has been proposed to have protective properties in OSCC patients. The aim of the present study was to correlate the GTn-repeat genotypes with clinicopathological characteristics along with clinical outcome of non-areca chewer OSCC patients. METHODS: DNA of 99 patients that underwent complete surgical resection of OSCC was analyzed for GTn-repeat polymorphism in the HMOX-1 promoter by polymerase chain reaction, capillary electrophoresis and DNA sequencing. RESULTS: Seven SS (7.1%), 51 SL (51.5%) and 41 LL (41.4%) genotypes were found. In a total of 14 (14.1%) patients, tumor recurrence (TR) was observed. There was no TR in the SS allele carriers. In SL carriers three and in LL 11 TR occurred (P = 0.009, chi-squared test). Mean relapse-free survival was 109.2 months in SL allele carriers compared with 72.3 months in LL allele carriers (P = 0.01, log-rank test). Multivariate Cox regression modeling identified GTn-repeat genotype as an independent prognostic factor (P = 0.03; relative risk (RR) 4.1; 95% CI 1.1-14.6). CONCLUSION: Presence of S allele was associated with a lower TR rate and better relapse-free survival in OSCC patients. HMOX-1 promoter polymorphism might be considered as a potential prognostic marker in OSCC patients.