Polymorphisms in the hypoxia inducible factor 1-alpha and the impact on the prognosis of early stages of oral cancer

Abstract

Background: Hypoxia-inducible factor-1 (HIF-1) is the key regulator of cellular responses to hypoxia and presumably plays a central role in the control of tumor growth. Polymorphisms or mutations increasing its activity and stability in vitro under normoxia have recently been identified. In this study, we aimed to investigate the effect of C1772T and G1790A single nucleotide polymorphisms (SNPs), located within the exon 12 of HIF-1alpha on the prognosis of early stages of oral squamous cell carcinoma (OSCC).

Methods: The frequency of C1772T and G1790A polymorphisms was determined by PCR-RFLP in 139 DNA samples from healthy volunteers and 74 patients with surgically treated T1/2 N0 OSCC. The impact of HIF-1alpha SNPs on tumor size, invasive depth, pathological features, and histological grade was studied. Correlations between genotype and relapse and/or disease-specific survival were evaluated by Kaplan-Meier analysis and log-rank test.

Results: Concerning G1790A SNP, the frequencies of GA heterozygous and AA variant homozygous genotypes were significantly higher in patients than in healthy volunteers (32.8% vs. 6.5% and 4.7% vs. none, respectively) (P < .0001). Also, the presence of the variant allele A was associated to disease-relapse (P = .02) and shorter disease-free survival (P = .04). The genotype distribution of C1772T did not diverge between patients and healthy subjects, and no differences were observed with respect to disease-free or overall survival.

Conclusions: Our results suggest that G1790A polymorphism in the HIF-1alpha gene might confer susceptibility to OSCC and could be a marker of disfavorable prognosis at early stages.