Molecular Evaluation of HIF-1α Gene Variation and Determination of Its Frequency and Association with Breast Cancer Susceptibility in Saudi Arabia.

Aim: Hypoxia-inducible factor 1 (HIF-1α) is responsible in regulating oxygen homeostasis in tissues and is a central effector of the hypoxic response besides its protein overexpression has been shown to have prognostic relevance in several cancers including breast cancer. Several reports indicated that HIF-1α gene variation C1772T (Pro582Ser) is associated with increased breast susceptibility but results remained controversial. Therefore, we performed the molecular evaluation of HIF-1α gene variation and determined its frequency and association with Breast Cancer susceptibility in Saudi Arabia.

Methods: This study was conducted on histologically confirmed Breast cancer patients and gender matched healthy women. HIF-1α C1772T (Pro582Ser) genotyping was done by Amplification refractory mutation system PCR method. The HIF-1α gene genotypes were correlated with different clinicopathological characteristics of breast cancer patients.

Results: A significant difference was observed in genotype distribution of HIF-1α gene variation C1772T (Pro582Ser) between breast cancer cases and gender matched healthy controls (P=0.010). Our findings showed that the HIF- 1α variant was associated with an increased risk of Breast cancer for HIF-1α CC vs CT genotype OR = 2.20, 95% CI = (1.28 -3.77), P = 0.004) in codominant inheritance model. The significant association was reported for HIF1A for genotypes CC vs (CT+ TT) OR = 1.98, 95% CI = (1.17-3.34), P = 0.010) in dominant inheritance model tested. In case of recessive inheritance model, a non-significant association of HIF-1 alpha gene variants was reported for (CC+ CT) vs TT) OR = 1.03, 95% CI = (0. 064-16.79), P = 0.97). During the allelic comparison, a non-significant association was reported between A vs C allele among Breast cancer patients. A significant association of HIF- 1α polymorphism was reported with stage as well as distant metastasis of the disease.

Conclusion: A significant difference was observed in genotype distribution of HIF-1α gene variation C1772T (Pro>Ser) between breast cancer cases and gene matched healthy controls (P=0.010). HIF-1α- CT heterozygosity and CC genotype increased the susceptibility .The HIF-1α polymorphism was reported to be significantly associated with the distant metastasis of Breast cancer. Further studies with larger data set and well-designed models are required to validate our findings.