Interleukin-33 [IL-33] is a specific ligand for the ST2 receptor, and a member of the
IL-1 family. It is a dual-function protein that acts both as an extracellular alarmin cytokine,
and an as an intracellular nuclear factor participates in maintaining barrier function by
regulating gene expression of IL-33 modulating tumor growth and anti-tumor immunity in
cancer patients. The present study aimed to investigate the role of IL-33 serum level and gene
polymorphism in Iraqi women with breast cancer. Materials and methods: Blood samples
were collected from 66 Iraqi patient women diagnosed with breast cancer, which were divided
into two groups: pre-treatment [PT] and under treatment with chemotherapy [UTC] patients in
addition to 34 apparently healthy women who were matched with patients as a control.
ELISA technique was used to determine the IL-33 serum level. The PCR-RFLP technique
was performed to determine IL-33 gene polymorphisms at single nucleotide polymorphism
SNP [rs1929992]. Results: IL-33 serum level recorded lower significant in PT [182.22 ±
29.86pg/ml] and UTC [129.87 ± 45.11pg/ml] patients compared with control [258.08 ± 39.54 pg/ml] under [p<0.05]. In a polymorphism study on IL-33 SNP [rs1929992] showed AG genotype recorded the high frequency in control than in patients [76.47, 58.46] compared to other genotypes AA, GG with no significant difference according to fisher’s exact probability. In conclusion: IL-33 serum level decreased after performing surgery on breast cancer patients. There was no association between breast cancer development and IL-33 SNP [rs1929992]. The heterozygous genotype AG was a common genotype in the Iraqi population. Allele G had an environmental fraction, while allele A had preventive fraction, which related to increasing the level of IL-33 with both genotypes AA, AG in the healthy control group, in contrast with GG genotype which showed the highest level in the patients’ group.