Analysis of polymorphism at site-174 G/C of interleukin-6 promoter region in multiple myeloma

It is well established that interleukin-6 ( IL-6) is an essential growth factor for multiple myeloma ( MM) and patients with increased IL-6 levels have a poor prognosis. In healthy subjects, the presence of the C allele at a polymorphic site (-174 G/ C) of the IL- 6 gene is related to low IL- 6 levels. In view of the potential association of this particular polymorphism with IL- 6 concentration, and the relevance of IL- 6 in MM pathogenesis, the objective of the present study was to investigate the prevalence of IL- 6 (- 174 G/ C) promoter polymorphism and its association with development of MM in Brazilian individuals. We investigated the prevalence of these alleles in 52 patients and 60 healthy subjects ( matched by age, sex, and race) of a Brazilian population. Thirty patients were male ( 42.4%), 24 ( 46.2%) were white and the median age at diagnosis was 58.5 years ( range: 28 to 84 years). To determine the IL- 6 (- 174 G/ C) polymorphism, molecular analysis was performed by polymerase chain reaction followed by endonuclease restriction digestion. The genotype distributions observed in the group of patients were 4% CC, 42% GC and 54% GG. The C allele frequency was 0.25. These results were similar to the control group, suggesting no impact of this polymorphism on the susceptibility to MM.