Objectives: Studies investigating associations between common polymorphisms in phase II metabolic enzymes COMT and SULT1A1 and the risk of various cancer types have revealed inconsistent and controversial results, with no attention turned to date to the most common adult leukemia type, i.e., chronic lymphocytic leukemia. Methods: In this small case-control study with 47 cases and 50 controls, the role of two functional polymorphisms, Val158Met in COMT gene and Arg213His in SULT1A1 gene affecting the activity level of respective enzymes, was studied on the susceptibility to chronic lymphocytic leukemia in an Estonian cohort. Results: Although statistically non-significant (p>0.05), the suggestive reduction in disease risk observed with low activity enzyme variants could indicate the involvement of O-methylation and sulfation of various endogenous and exogenous substances in the process of leukemogenesis. The odds ratio (OR) for Met158Met genotype of COMT was 0.60 with 95% confidence interval (95% CI) 0.20-1.82 compared to the wild type Val158Val genotype and the OR for His213His genotype of SULT1A1 was 0.58 with 95% CI 0.20-1.71 compared to the wild type Arg213Arg genotype. Conclusion: Further large-scale studies are highly needed to confirm or disprove the findings of the present study and determine genetic risk factors for chronic lymphocytic leukemia. Keywords: Chronic lymphocytic leukemia, O-methylation, phase II enzyme, single nucleotide polymorphism, sulfate conjugation
Corresponding Author: Sak K.