Abstract

Breast cancer is a common malignant tumor in females worldwide. Inducible costimulator (ICOS) is an immune-related gene, and its abnormal expression can disturb the immune function and lead to an increased risk of cancer. The present study investigated if there any association between single nucleotide polymorphisms (SNPs) in the ICOS gene and breast cancer risk in Egyptian women. Five SNPs in ICOS gene were genotyped among 150 breast cancer patients and 100 healthy controls using PCR-RFLP. The results showed that ICOS rs11889031 TT genotype and T allele, rs4675374 and rs10183087 CC genotypes, as well as rs10932037 CT genotype of breast cancer cases elicited higher frequencies as compared with controls. On the other hand, ICOS rs4675374 and rs10183087 CT genotype frequencies were lower in breast cancer cases compared to controls. However, ICOS rs10932029 showed non-significant differences of all genotype and allele frequencies of breast cancer cases compared to controls. By testing the haplotypes distribution, the frequency of CTTAC haplotype was significantly higher in breast cancer cases compared to controls. This study is the first to establish that some of SNPs in the ICOS gene polymorphism may affect breast cancer progression among Egyptian women.

Key words: Breast cancer – Inducible costimulator – Gene polymorphism –Genotype – Haplotype.