Education, tobacco smoking, alcohol consumption, and IL-2 and IL-6 gene polymorphisms in the survival of head and neck cancer

• Main Authors: R.V.M. López, M.A. Zago, J. Eluf-Neto, M.P. Curado, A.W. Daudt, W.A. da Silva-Junior, D.L. Zanette, J.E. Levi, M.B. de Carvalho, L.P. Kowalski, M. Abrahão, J.F. de Góis-Filho, P. Boffetta, V. Wünsch-Filho
• Format: Article
• Language: English
• Published: Associação Brasileira de Divulgação Científica 2011-10-01
• Series: Brazilian Journal of Medical and Biological Research
• Subjects: Smoking; Alcohol; Interleukin; Head and neck cancer; Cancer prognosis; Survival analysis
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011001000005&lng=en&tlng=en

The association of education, tobacco smoking, alcohol consumption, and interleukin-2 (IL-2 +114 and -384) and -6 (IL-6 -174) DNA polymorphisms with head and neck squamous cell carcinoma (HNSCC) was investigated in a cohort study of 445 subjects. IL-2 and IL-6 genotypes were determined by real-time PCR. Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (95%CI) of disease-specific survival according to anatomical sites of the head and neck. Mean age was 56 years and most patients were males (87.6%). Subjects with 5 or more years of schooling had better survival in larynx cancer. Smoking had no effect on HNSCC survival, but alcohol consumption had a statistically significant effect on larynx cancer. IL-2 gene +114 G/T (HR = 0.52; 95%CI = 0.15-1.81) and T/T (HR = 0.22; 95%CI = 0.02-3.19) genotypes were associated with better survival in hypopharynx cancer. IL-2 +114 G/T was a predictor of poor survival in oral cavity/oropharynx cancer and larynx cancer (HR = 1.32; 95%CI = 0.61-2.85). IL-2 -384 G/T was associated with better survival in oral cavity/oropharynx cancer (HR = 0.80; 95%CI = 0.45-1.42) and hypopharynx cancer (HR = 0.68; 95%CI = 0.21-2.20), but an inverse relationship was observed for larynx cancer. IL-6 -174 G/C was associated with better survival in hypopharynx cancer (HR = 0.68; 95%CI = 0.26-1.78) and larynx cancer (HR = 0.93; 95%CI = 0.42-2.07), and C/C reduced mortality in larynx cancer. In general, our results are similar to previous reports on the value of education, smoking, alcohol consumption, and IL-2 and IL-6 genetic polymorphisms for the prognosis of HNSCC, but the risks due to these variables are small and estimates imprecise.