Second primary tumours are still a challenge in patients treated for oral squamous cell carcinomas (OSCC). Hypoxia Inducible Factor-1 Alpha (HIF-1α) polymorphisms have been correlated with susceptibility to head and neck carcinomas in a previous study of the group, however their influences in these second neoplasms need to be studied. Genotypic distribution of C1772T and G1790A polymorphisms is analyzed in a series of 124 patients with early-stage OSCC (pT1 and pT2) and in 26 patients of this group with second primary tumours. Frequencies of polymorphic T and A alleles between patients and a sample of healthy subjects were compared using the Chi square test. Survival analysis of second primary tumours was also studied with Kaplan-Meier curves and Long-rank test. G1790A polymorphism was associated with second primary tumours as A allele was most frequent in patients than in healthy subjects (50% and 6.5% respectively; p<0.01). This polymorphism was also correlated with the development of intraoral carcinomas (frequency of A allele of 39.7% in patients and 6.5% in healthy subjects; p<0.01). Survival rate for patients with secondary neoplasms was lower than patients without this condition (78.9% 5-year cumulative survival rate and 92.4% respectively; p<0.01). G1790A is a factor of susceptibility to intraoral carcinomas and to second primary tumours in patients treated for OSCC. Patients with secondary neoplasms have poorer prognosis, so they may need more aggressive therapies and long-term follow-up.
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