Association of circadian BMAL1 gene expression and its polymorphism and risk of breast cancer in females

Abstract

ObjectiveBreast cancer as the principal reason for cancer mortality in females. Any abnormalities in the circadian might increase breast cancer progression. The aim was to examine the association between a genetic variant in the circadian gene BMAL1 and the chance of developing breast cancer, as well as the effect of gene expression of the circadian gene on breast cancer tissue. Patients and methodsThis study conducted on 100 subjects: 50 breast cancer cases and 50 age-matched healthy women. All subjects had a complete medical history, general clinical examination, mammography, and laboratory investigations, including serum CEA and serum CA15-3, and detection of circadian BMAL1 (rs2279287) genotypes and its MRNA expression by real-time PCR. ResultsSerum CA15.3 levels were greater in breast cancer cases than in controls. The frequency of T/C and T/T genotypes is considerably greater in breast cancer patients. BMAL1 expression was higher in breast cancer tissues with a TC/TT genetic variance. The expression of the circadian gene BMAL1 was found to be significantly related to tumor status, relapse status, and BMAL1 genotypes. BMAL1 genotypes were associated with pathological stage and grade. Women with the T/C genotype had a greater risk of ER-/PR-tumors than ER+/PR-tumors. ConclusionCircadian BMAL1 gene was more common TC/TT genotypes than CC genotypes. BMAL1 expression was lower in breast cancer tissues with a TC/TT genetic variance, so BMAL1 may have a role in the development of breast cancer.