Introduction: We investigated the associations between -174 G/C polymorphism of interleukin-6 (IL-6) gene promoter and serum IL-6 and carcinoembryonic antigen (CEA) levels in Taiwanese patients with colorectal cancer (CRC).
Results and discussion: The frequency of the G allele was only 0.043, which is significantly lower compared to Western analogs. On grouping genotypes as G-positive (GG and CG) and G-negative (GG), the average IL-6 level and CEA levels were significantly lower in G-positive patients than in G-negative analogs (IL-6, 3.56 +/- 4.38 vs. 15.38 +/- 9.52 pg/ml, P = 0.021; CEA, 27.7 +/- 25.7 vs. 157.7 +/- 59.6 ng/ml, P = 0.012). The patients without the G allele had higher incidences of synchronous cancers of other origins (P = 0.003).
Conclusion: In conclusion, ethnicity affects the status of -174 G/C IL-6 polymorphism. This polymorphism status consequently influences the expressions of serum IL-6 and CEA and incidences of synchronous cancers of other origins.