Abstract:Previous reports show a hypermethylation of estrogen receptor 1 (ESR1) gene promoter in cervical carcinoma and it was suggested that this may lead to down regulation of gene expression or gene silencing. This paper studies the association of ESR1 loss at the protein level with the cervical disease pathogenesis, and its relation to ethnic differences between Uighur and Han women. A total of 180 cases of formalin fixed and paraffin-embedded cervical tissue specimens were collected from Uighur and Han women with cervicitis, cervical intraepithelial neoplasia (CIN) I/II/III and cervical squamous cell carcinoma, and the ESR1 protein expression was detected by immunohistochemistry. Experimental results show that ESR1 protein is ubiquitously expressed in both epithelial and stroma cells of the uterine cervix, but gradually lost in epithelial cells with the development of CIN and cervical squamous cell carcinoma. The loss rate of ESR1 protein expression is relatively low in the group of cervicitis and CIN I, is markedly increased in the group of CIN II/III (64%), to reach the highest level in cervical carcinoma (76%), and the difference is significant among groups (P<0.01), but no statistical difference in ages of the individuals (P>0.05); the alteration trend of the loss rate of ESR1 is common to women from both Uighur and Han ethnic groups, and the difference between two ethnic groups is also not statistically significant (P>0.05). These results indicate that the loss of ESR1 expression may be an early prediction marker of cervical squamous cell carcinoma, which may serve as an important evidence for revealing epigenetic mechanisms related to the hypermethylation of this gene.