Background The ESR 1 gene suffers methylation changes in many types of cancers, including breast cancer (BC), the most frequently diagnosed cancer in women that is also present in men.… Click to show full abstract
Background The ESR 1 gene suffers methylation changes in many types of cancers, including breast cancer (BC), the most frequently diagnosed cancer in women that is also present in men. Methylation at promoter A of ESR 1 is the worse prognosis in terms of overall survival; thus, the early detection, prognostic, and prediction of therapy involve some methylation biomarkers. Methods Therefore, our study aimed to examine the methylation levels at the ESR 1 gene in samples from Mexican BC patients and its possible association with menopausal status. Results We identified a novel 151-bp CpG island in the promoter A of the ESR 1 gene. Interestingly, methylation levels at this CpG island in positive ERα tumors were approximately 50% less than negative ERα or control samples. Furthermore, methylation levels at ESR 1 were associated with menopausal status. In postmenopausal patients, the methylation levels were 1.5-fold higher than in premenopausal patients. Finally, according to tumor malignancy, triple-negative cancer subtypes had higher ESR 1 methylation levels than luminal/HER2+ or luminal A subtypes. Conclusions Our findings suggest that methylation at this novel CpG island might be a promising prognosis marker
               
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