Insulin-like growth factor 1 gene olymorphism and breast ancer risk among arab omani women: A case-control study

Breast cancer is the most common cancer worldwide with significant global burden. Insulin-like growth factor 1 (IGF1) is an important regulator of cellular growth, differentiation, and apoptosis and mitogenic and antiapoptotic activities. Some studies suggested an association between cytosine adenine (CA) repeats gene polymorphisms of IGF1 and the risk of developing breast cancer while other studies did not find such an association. This study aims investigate the role of IGF1 (CA) repeats gene polymorphisms in the risk of developing breast cancer among Omani women. Methods: We analyzed (CA) repeats gene polymorphisms of IGF1 by extraction of genomic DNA from the peripheral blood of 147 patients with breast cancer and 134 control participants and performed genotyping using DNA sequencing. Results: Approximately 46% of patients carried the IGF (CA)₁₉ repeat allele, with 31.3% carrying two copies of this allele and 50% of controls carried the IGF (CA)₁₉ repeat allele with 30.1% carrying two copies of this allele. The difference of the IGF CA repeat groups was significant between cases and controls with (P = 0.02). In contrast, there was no difference in the distribution of (CA)₁₉ repeat allele, (CA)18 repeat allele and (CA)₁₉ repeat allele between cases and controls. The difference of the CA groups was significant between cases and controls among postmenopausal women with (P = 0.026), whereas no difference was observed among postmenopausal subjects (P = 0.429). In both pre- and postmenopausal groups there was no difference in the distribution of (CA)₁₉ repeat allele, (CA)₁₈ repeat allele and (CA)₂₀ repeat allele between patients and control subjects. On further IGF1 genotypes classification, we found an association between progesterone receptor status and the genotypes group where the non carrier of (CA)₁₉ repeat group was compared to (CA)₁₉ repeat carrier group (OR = 2.482; 95% CI = 1.119-5.503; P value = 0.023). Conclusion: Overall there was no association between the IGF (CA)₁₉ repeat and breast cancer in Omani females.