Effect of IL-18 gene promoter polymorphisms on prostate cancer occurrence and prognosis in Han Chinese population

J.M. Liu, J.N. Liu, M.T. Wei, Y.Z. He, Y. Zhou, X.B. Song, B.W. Ying, J. Huang
Published: March 15, 2013
Genet. Mol. Res. 12 (1) : 820-829
DOI: https://doi.org/10.4238/2013.March.15.2

Cite this Article:
J.M. Liu, J.N. Liu, M.T. Wei, Y.Z. He, Y. Zhou, X.B. Song, B.W. Ying, J. Huang (2013). Effect of IL-18 gene promoter polymorphisms on prostate cancer occurrence and prognosis in Han Chinese population. Genet. Mol. Res. 12(1): 820-829. https://doi.org/10.4238/2013.March.15.2

About the Authors
J.M. Liu, J.N. Liu, M.T. Wei, Y.Z. He, Y. Zhou, X.B. Song, B.W. Ying, J. Huang

Corresponding Author
J. Huang

Email: michael.huangjin@gmail.com

ABSTRACT
Interleukin-18 (IL-18) has been implicated in a wide variety of cellular functions that affect the biological response to tumors. However, there is insufficient evidence to prove that IL-18 gene variants are associated with risk of prostate cancer. We examined a possible association between two promoter polymorphisms, -137G/C (rs187238) and -607C/A (rs1946518), in the IL-18 gene and prostate cancer occurrence and prognosis in Han Chinese. We used a high-resolution melting method to genotype these two polymorphisms in 375 Chinese Han patients with prostate cancer and in 400 age-matched healthy controls. A hundred and eighty-one prostate cancer patients who had been receiving androgen deprivation therapy, including operational and medical castration, were enrolled to follow-up in this study. Carriers of the GG genotype of the -137G/ C polymorphism had a 2.165-times higher risk of prostate cancer progression than carriers of GC [95% confidence interval (CI) = 1.270-3.687]. Patients with the GG genotype at clinical stages III and IV also had significantly lower rates of progression-free survival (relative risk = 2.174, 95%CI = 1.211-3.906). However, we found no significant association of genotype or allele distributions of these two polymorphisms with occurrence of prostate cancer. We conclude that there is evidence that the IL-18 gene promoter polymorphism -137G/ C influences the prognosis of prostate cancer patients in androgen deprivation therapy, although neither of the two SNPs contributes to prostate cancer development.

Interleukin-18 (IL-18) has been implicated in a wide variety of cellular functions that affect the biological response to tumors. However, there is insufficient evidence to prove that IL-18 gene variants are associated with risk of prostate cancer. We examined a possible association between two promoter polymorphisms, -137G/C (rs187238) and -607C/A (rs1946518), in the IL-18 gene and prostate cancer occurrence and prognosis in Han Chinese. We used a high-resolution melting method to genotype these two polymorphisms in 375 Chinese Han patients with prostate cancer and in 400 age-matched healthy controls. A hundred and eighty-one prostate cancer patients who had been receiving androgen deprivation therapy, including operational and medical castration, were enrolled to follow-up in this study. Carriers of the GG genotype of the -137G/ C polymorphism had a 2.165-times higher risk of prostate cancer progression than carriers of GC [95% confidence interval (CI) = 1.270-3.687]. Patients with the GG genotype at clinical stages III and IV also had significantly lower rates of progression-free survival (relative risk = 2.174, 95%CI = 1.211-3.906). However, we found no significant association of genotype or allele distributions of these two polymorphisms with occurrence of prostate cancer. We conclude that there is evidence that the IL-18 gene promoter polymorphism -137G/ C influences the prognosis of prostate cancer patients in androgen deprivation therapy, although neither of the two SNPs contributes to prostate cancer development.

Key words: IL-18, Prostate cancer, Polymorphism.

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